JPH0964601A - High frequency circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a high frequency circuit to be used for a radio equipment utilizing high frequency such as microwaves to respond to plural frequencies while attaining the reduction of its size and cost. SOLUTION: A transmission line 16 consisting of a microstrip line to be a partial constitutional element is used for all frequencies in common so that the high frequency circuit can respond to plural frequencies. A transmission line 17 consisting of a microstrip line to be the other constitutional element is connected or separated to/from the line 16 in accordance with a frequency which is used.

Description

Detailed Description of the Invention

(Technical Field of the Invention) Technical Field of the Invention Conventional Technology (FIGS. 52 to 64) Problems to be Solved by the Invention (FIGS. 52 to 67) Means for Solving the Problems Embodiments of the Invention (1) Description of bias circuit used in high frequency amplifier (FIGS. 1 to 20) (2) Description of high frequency amplifier (FIGS. 21 to 26) (3) Description of directional coupler (FIG. 27) (4) Description of high frequency filter circuit Description (FIGS. 28 to 38) (5) Description of Voltage Controlled Oscillator (FIGS. 39 to 51)

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency circuit used in a radio device using high frequency waves such as microwaves, and more particularly to a high frequency circuit suitable for use in the high frequency part of a mobile phone. Currently, in mobile communication systems such as mobile phones using microwaves, the 800 MHz band is mainly used as a usable frequency including analog and digital. In recent years, price reduction of mobile devices (particularly mobile phones) has been achieved. 1.55GH mainly in the Tokyo metropolitan area in order to ease congestion of communication traffic due to the rapid increase in the number of users
The use of the z band has also started.

However, currently available portable devices are preset with usable bands (frequency bands) such as 800 MHz band and 1.55 GHz band. If the number increases further, it will not be able to handle all communications. In addition, as described above, in a mobile device that can use only one of the bands, the usage area is limited at present.

Therefore, in recent years, 800 MHz band, 1.
There has been a demand for a dual band portable device that can be used in either of the 55 GHz bands, and along with this, the high frequency part (high frequency circuit) of the portable device is compact and has multiple frequencies (800 MHz, 1.55 GHz). ) Is needed.

[0005]

2. Description of the Related Art FIG. 52 is a block diagram showing a configuration of a conventional general mobile phone. The mobile phone shown in FIG. 52 has a variable attenuator (VATT) 10 as a transmission system 100.
1, direct modulator (MOD) 102, high power amplifier (HP
A) 103, hybrid (HYB: directional coupler) 1
04, a detection circuit 60, a comparison circuit 70, and a bandpass filter (BPF) 105, and a bandpass filter (BPF) 201, a low noise amplifier (L) as a reception system 200.
NA) 202 and reception down converter (MIX) 20
It is configured with three.

Note that the antenna 400 is shared by the transmission system 100 and the reception system 200 via the duplexer 300, and RF
Local oscillator (voltage controlled oscillator) 500 for (high frequency) band
Is also shared by the transmission system 100 and the reception system 200. In the mobile phone configured as described above, first, the transmission signal has an optimum signal level by controlling the attenuation degree of the variable attenuator 101 according to feedback control by the detection circuit 60 and the comparison circuit 70 described later. Adjusted.
Further, this transmission signal is simultaneously modulated and frequency-converted by the direct modulator 102 together with the output from the local oscillator 500, and is amplified by the high-power amplifier 103.

At this time, in the local oscillator 500,
If the portable device is for the 800 MHz band, the one for the 800 MHz band is used, and for the 1.55 GHz band, the one for the 1.55 GHz band is used. Therefore, the output of the high output amplifier 103 has a frequency corresponding to this. An RF (high frequency) signal having After that, this transmission RF signal has a noise component removed by the bandpass filter 105, and the frequency is 800 MHz.
z-band or 1.55 GHz band signal is passed,
The antenna 4 via the duplexer 300 as the transmission signal f _T
Sent from 00.

By the way, at this time, in the detection circuit 60,
By detecting a part of the transmission RF signal branched by the hybrid 104, the signal level is converted to a DC level and output to the comparison circuit 70. The comparison circuit 70 outputs this DC level and the high output amplifier 103. The error voltage is detected by comparing with the reference voltage corresponding to the specified transmission output, and the variable attenuator 10 is used using this error voltage.
1 is feedback-controlled to maintain the output level of the transmission signal f _T constant.

On the other hand, the received RF signal f _R from the antenna 400 is similarly removed in the 800 MHz band or 1.
The signal of 55 GHz band is passed and the low noise amplifier 20
After being amplified to a required signal level in 2, the receiving down converter 203 frequency-converts the signal into an IF (intermediate frequency) signal according to the output from the local oscillator 500 and outputs it to a circuit in the subsequent stage.

Now, here, the high frequency amplifier (high output amplifier 10) used in the high frequency part of the above-mentioned portable telephone is used.
3, low noise amplifier 202), high frequency filter circuit (bandpass filters 105 and 201), voltage controlled oscillator (local oscillator 500), directional coupler (hybrid 1)
Each high frequency circuit of 04) will be described in detail below item by item.

(1) Description of Conventional High-Frequency Amplifier Since an amplifier is usually composed of a large number of transistors, a bias circuit for obtaining a required operating point of the transistors is required as is well known. FIG. 53 is a diagram showing a configuration of a bias circuit generally used for an amplifier in the above-mentioned mobile phone. In FIG. 53, 111 is a grounded-emitter transistor for amplifying an input signal, and 112 is a grounded-emitter transistor.
Is the frequency band used (800MHz band or 1.55G
The transmission line (S1) having a length of λg / 4, where 113 is the transistor 1
A power source for 11, C100 is a capacitor through which only a signal in the used frequency band passes.

With such a configuration, in the above-mentioned bias circuit, when a signal (wavelength λg) having a used frequency is input, this signal is generated at 90 degrees near both ends of the transmission line 112.
Since the capacitors C100 pass through the capacitors C100 differently, one end of the transmission line 112 is open (open) and the other end is short-circuited. Therefore, this bias circuit has almost no reflected wave signal (return loss is small) for signals having frequencies near the operating frequency band, and the passing loss between the input and output is small. The band signal will pass without loss.

For example, if the frequency band used by a mobile phone is 8
When 950 MHz is selected as the frequency close to 00 MHz and the length of the transmission line 112 is set to 1/4 of the wavelength of the signal of 950 MHz, the simulation is performed.
As shown in FIG. 57, the return loss (S11) seen from the input side, the return loss (S22) seen from the output side, and the passage loss (S12, S21) between the input and output are 9 respectively.
Since it shows the best characteristics around 50MHz, this 950
Signals in the MHz band pass through with the least loss.

On the other hand, similarly, the used frequency band is 1.55.
When a frequency of 1.44 GHz is selected as a frequency close to GHz and the length of the transmission line 112 is set to 1/4 of the wavelength of the signal of 1.44 GHz, the simulation is performed. In this case, FIGS. 58 to 61 are shown. As described above, S11 and S
Since 22, S12 and S21 each have the best characteristics in the vicinity of 1.44 GHz, the signal in the 1.44 GHz band passes the most without loss.

(2) Description of Conventional Directional Coupler FIG. 62 is a diagram showing an example of the configuration of a conventional directional coupler (hybrid 104: see FIG. 52) used in the above-mentioned portable telephone. In the figure, 141 and 142 are transmission lines respectively configured by using microstrip lines and the like, and by setting the length L ₆ of the transmission line 142 to 1/4 of the wavelength λg of the signal in the frequency band used, A coupler having characteristics corresponding to the frequency band used by the telephone is constructed.

That is, in this conventional directional coupler, for example, the transmission line length L _{6 is set} to 1 / the wavelength of the signal of 800 MHz.
If set to 4, it becomes a coupler for 800MHz band,
If set to 1/4 of the wavelength of the signal of 1.55 GHz,
It becomes a coupler for the 1.55 GHz band. (3) Description of Conventional High-Frequency Filter Circuit FIG. 63 (a) is a diagram showing an example of the configuration of the high-frequency filter circuit (bandpass filters 105, 201) in the above-mentioned mobile phone. In FIG. 63 (a), 115 Is a dielectric resonator (DR), 116 is a signal line, and C200 is a capacitor. Note that FIG. 63 (b) is shown in FIG. 63 (a).
The high-frequency filter circuit having the unit configuration shown in FIG.
It is a figure which shows the structure connected to 2 stages in parallel.

Here, in the dielectric resonator 115, when the frequency to be passed is f ₀ (in this case, 800 MHz or 1.55 GHz), its length L ₇ is the wavelength of the signal of this frequency f _0. by setting to 1/4 of the lambda] g, in which open end with respect to the signal of frequency f _0, the other end becomes short, thereby, signals of frequency f ₀ is passed, other frequency bands The signal can be attenuated.

The capacitor C200 determines the amount of coupling between the dielectric resonator 115 and the signal line 116. However, in that case, the length L ₇ of the dielectric resonator 115 needs to be finely adjusted. (4) Description of Conventional Voltage Controlled Oscillator Conventionally, the voltage controlled oscillator (local oscillator 500: see FIG. 52) used in the above-mentioned mobile phone is unadjusted and accurate due to deviations and errors of circuit constants. It is difficult to obtain a proper transmission frequency. Especially, 800MHz, 1.55
As a voltage controlled oscillator used in a high frequency band such as GHz, a voltage controlled oscillator using a stripline resonator is often used in terms of resonance selectivity and cost.

FIG. 64 is a diagram showing an example of the configuration of a conventional general voltage controlled oscillator. In FIG. 64, 121 is a resonance circuit section, 122 is an oscillation circuit section, and the resonance circuit section 1 is shown.
21 is configured using a coil (L) 123, a variable capacitance diode (D) 124, a capacitor (C) 125, and a strip line 126, and the oscillation circuit unit 122 includes
This is an application of a so-called Colpitts type oscillation circuit, which is configured by using transistors and capacitors (C) 128 to 132.

As shown in FIG. 64, the resonance circuit section 121 is composed of an LC resonance circuit in which the other end of the strip line 126 is grounded, and is supplied to a variable capacitance diode 124 connected in parallel with the LC resonance circuit. The resonance frequency (oscillation frequency) is changed by varying the control voltage (V _C ) to be generated, so that a desired oscillation frequency can be obtained.

[0021]

However, each of such high-frequency circuits (high-frequency amplifier, high-frequency filter circuit, voltage-controlled oscillator, directional coupler) is
Since usable frequency bands are set in advance such as for the 00 MHz band and for the 1.55 GHz band, it is very difficult to use the frequency bands other than those.

For example, in the bias circuit described above with reference to FIG. 53 in item (1), as can be seen from the simulation results shown in FIGS. 54 to 61, the return loss (S11,
S22) and passing loss (S12, S21) are preset frequency bands (950 MHz band, 1.44 GHz band)
It hardly works in other frequency bands. So 80
To realize a bias circuit capable of supporting both the 0 MHz band and the 1.55 GHz frequency band, for example,
It is conceivable that two circuits preset for the 800 MHz band and 1.55 GHz band are prepared and these circuits are switched and used according to the used frequency. However, since the circuit scale is significantly increased, there is a problem in that it is very disadvantageous to use as a circuit for a mobile device such as a mobile phone in terms of cost.

Also, the directional coupler described above with reference to FIG. 62 in item (2) is very difficult to use in frequency bands other than the preset frequency band.
It is virtually impossible to support both the 00 MHz band and the 1.55 GHz band. So, even in this case, 800M
It is conceivable that two directional couplers for the Hz band and the 1.55 GHz band are connected in parallel via a switch or the like, and both frequency bands can be dealt with by switching the switches. Also in terms of circuit scale, it is extremely disadvantageous as a circuit for portable devices such as mobile phones.

Similarly, the conventional high frequency filter circuit described in the item (3) cannot be used for both frequency bands because the used frequency band is set in advance.
Therefore, as a high frequency filter circuit adapted to support both frequency bands, for example, a circuit as shown in FIG. 65 can be considered. That is, the high frequency filter circuit shown in FIG. 65 has different frequency bands f ₁ (for example, 800 MHz) and f ₂ (for example, 1.55 GHz).
Band pass filter (BPF) 11 that passes the signal of
7A and 117B and the respective dielectric resonators 118 and 119 are arranged in parallel. At this time,
Each of the band pass filters 117A and 117B adjusts the phase by adjusting the lengths L ₈ and L ₉ of the dielectric resonators 118 and 119 so that they are open with respect to the signals in the frequency bands on the other side. Adjusted.

As a result, in the above high frequency filter circuit, the signal of frequency f _{1 and} the signal of frequency f ₂ are passed,
In addition, signals in other bands can be attenuated (attenuated between f ₁ and f ₂ ). However, as is clear from FIG. 65, the circuit scale of such a high-frequency filter circuit also increases significantly, which is also extremely disadvantageous as a circuit for a portable device such as a mobile phone.

Further, in the conventional voltage controlled oscillator described above with reference to FIG. 64 in item (4), the oscillation frequency is usually 8 in advance.
Since it is set to either the 00 MHz band or the 1.55 GHz band, the 800 MHz band and the 1.55 GHz band
It is very difficult to realize an oscillator having a wide band modulation sensitivity characteristic that can oscillate a signal in a frequency band about twice as wide as a band.

Further, a voltage controlled oscillator having such characteristics has a structure similar to that of the voltage controlled oscillator shown in FIG. 64 for 800 MHz band, as shown in FIG.
Two oscillators 134A and 134 for the 1.55 GHz band
B, or as shown in FIG. 67, the voltage controlled oscillator modules (VCO modules) 135A and 135B are individually provided and connected in parallel via the switch (SW) 133, and used frequency bands (800 MHz, 1.55 G
This can be realized by switching the switch 133 depending on the frequency (Hz), but in this case as well, the circuit scale obviously increases significantly, so it is also suitable for use as a circuit for portable devices such as mobile phones. Is very disadvantageous.

Further, in the above-mentioned conventional voltage controlled oscillator, the fine adjustment of the oscillation frequency is performed by directly trimming the strip line used in the resonance circuit section 122. This adjustment becomes very difficult if the stripline is formed on the inner layer of the substrate. On the other hand, even when this stripline is formed on the surface of the substrate, the substrate is usually covered with a metal shield case after such adjustment of the oscillation frequency, so the oscillation frequency considering the influence of disturbance such as the case is considered. Fine tuning is still required, and such fine tuning becomes extremely difficult after the oscillator is manufactured as a module.

The present invention was conceived in view of the above problems, and an object thereof is to provide a high frequency circuit which is small in size and low in cost, and which can cope with a plurality of frequencies.

[0030]

Therefore, the high frequency circuit of the present invention according to claim 1 is designed to support a plurality of frequencies.
Some components are shared for all frequencies, and other components are configured to be connected or disconnected to this some components according to the frequency used (hereinafter, the circuit configured as described above). Is referred to as a pattern A circuit).

Further, in the high frequency circuit of the present invention as defined in claim 2, some components are commonly used for all frequencies in order to cope with a plurality of frequencies, and other components are used in accordance with the used frequency. It is configured so that the impedance can be changed (hereinafter, the circuit configured as described above is used as a pattern B).
Of the circuit). Furthermore, the high-frequency circuit of the present invention according to claim 3 is provided with a plurality of matching circuits in order to correspond to a plurality of frequencies, and these matching circuits are respectively connected via a demultiplexing / combining circuit (hereinafter, referred to as above. A circuit configured as described above is referred to as a pattern C circuit).

[0032]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an example of the configuration of a mobile phone to which a high frequency circuit according to an embodiment of the present invention is applied. The mobile phone shown in FIG.
Similar to the mobile phone shown in FIG. 1, as the transmission system 1, a variable attenuator (VATT) 2, a direct modulator (MOD) 3, a high output amplifier (HPA) 4, a hybrid (HYB: directional coupler) 5, a bandpass. Filter (BPF) 6, Detection circuit 7
And a comparison circuit 8 and a reception system 9 including a bandpass filter (BPF) 10, a low noise amplifier (LNA) 11 and a reception down converter (MIX) 12.

In this case as well, the antenna 13 is shared by the transmission system 1 and the reception system 9 via the duplexer 14, and RF
The local oscillator (voltage controlled oscillator) 15 for the (high frequency) band is also shared by the transmission system 1 and the reception system 9. Therefore, each of these components is basically the same as that described above with reference to FIG. 52, but the mobile phone shown in FIG. 1 has, for example, both frequencies of 800 MHz band and 1.55 GHz band. A high-frequency amplifier (high-output amplifier 4, low-noise amplifier 11), a directional coupler (hybrid 5), a high-frequency filter circuit (band-pass filter 6) provided in the high-frequency part so that the band can be used as a frequency band to be used. Each high frequency circuit is configured to support both frequency bands.

Each of these high-frequency circuits, which are the essential parts of the present invention, will be described in detail below item by item. (1) Description of Bias Circuit Used in High-Frequency Amplifier FIG. 2 is a diagram showing the configuration of the bias circuit used in the high-frequency amplifier in the mobile phone of the present embodiment. In FIG. 2, 16 and 17 are microstrip lines, etc., respectively. , And transmission lines C2 and C3 are capacitors. In addition, G is a ground.

Here, the transmission lines 16 and 17 delay the input RF signals according to their lengths, and the wavelength of a signal having a frequency f ₁ (for example, 800 MHz) is λg. ₁ , frequency f ₂ (for example, 1.55
The wavelength of the signals with GHz) when the lambda] g _2, while the length of the transmission line 16 is "S2" is set to λg _2/4, the length of the transmission line 17 "S3" is in "S2 + S3" λ
such that g _{1/4 (i.e., S3 = λg 1/4-} S
2).

Further, the capacitor C2 passes only the signal of the frequency f ₂ , and the capacitor C3 passes only the signal of the frequency f _1. For example, the bias circuit receives the signal of the frequency f ₂ . When input, this signal flows to the capacitor C2 through the transmission line 16, while when a signal of frequency f ₁ is input, this signal flows to the capacitor C3 through the transmission lines 16 and 17.

With such a configuration, in the above-described bias circuit, when a signal in the 1.55 GHz band is input, for example, this signal flows to the capacitor C2 through the transmission line 16. At this time, this signal is Transmission line 16
In by the delay is performed in accordance with the length "S2 (= λg _2/4)", the phase of each other signal at both ends of the transmission line 16 is 90 ° different states.

As a result, one end of the transmission line 16 is short-circuited and the other end is open, and the transmission line 17 is disconnected from the transmission line 16. Is the used frequency of 1.5
For signals in the 5 GHz band, capacitors C2 and C3
The reflected wave signal flowing from the transmission line 16 to the transmission line 16 almost disappears, and the input signal in the 1.55 GHz band is output without loss.

On the other hand, when a signal 800MHz band is entered, the signal flows to the capacitor C3 through the transmission lines 16 and 17, the length in the transmission lines 16, 17 _{'S2 + S3 (= λg 1/} 4) The transmission lines 16 and 17 have a length of "S2 +"
If it is regarded as one transmission line having "S3", the phases of the signals are different from each other by 90 ° at both ends thereof.

Therefore, in this case, each transmission line 16, 1
When 7 is regarded as one transmission line having a length “S2 + S3”, one end thereof is short-circuited and the other end is open, and the transmission line 17 is connected to the transmission line 16, Even for the signal of 800 MHz band which is the other used frequency, the reflected wave signal flowing from each of the capacitors C2 and C3 toward the transmission line 16 almost disappears,
The input 800 MHz band signal is output without loss.

That is, the bias circuit (high frequency circuit) shown in FIG. 2 has a frequency f ₁ (800 MHz) and a frequency f.
_In order to support two frequencies of ₂ (1.55 GHz), the transmission line 16 which is a part of the components is shared for all frequencies f ₁ and f ₂ , and the transmission line 17 which is another component is used. The transmission line 16 is connected or disconnected according to the frequencies f ₁ and f ₂ (that is, this bias circuit corresponds to the circuit of pattern A).

Therefore, according to the bias circuit (high frequency circuit) as one embodiment of the present invention, as in the conventional case, 80
Even if a bias circuit having characteristics corresponding to two frequency bands of 0 MHz band and 1.55 GHz band is not separately provided, it is apparent that one circuit is 800 MHz band,
It has become possible to support both frequencies in the 1.55 GHz band, which makes it possible to realize a bias circuit compatible with two frequency bands without increasing the circuit scale, and it is difficult to achieve low cost and downsizing. The circuit can be sufficiently applied as a circuit for a mobile phone that requires conditions.

It should be noted that FIGS. 3 to 6 show the operating frequency of the bias circuit constructed as described above at 800
9 for frequencies close to MHz and 1.55 GHz, respectively
It is a figure which shows an example of a result at the time of choosing 50 MHz and 1.44 GHz and performing a simulation, and shows return loss (S11) seen from the input side which shows the influence of a reflected wave signal, as each shown in FIG. 3 and FIG. , Return loss (S22) seen from the output side is 950MHz and 1.44, respectively.
It can be seen that it becomes the smallest in the vicinity of GHz, and as shown in FIGS. 5 and 6, the passing loss (S12, S21) between the input and output also becomes the smallest in the vicinity of 950 MHz and 1.44 GHz, respectively.

(1-1) Description of First Modification of Bias Circuit FIG. 7 is a diagram showing a first modification of the bias circuit described above with reference to FIG. 2. In FIG. 7, 18 is a microstrip line or the like. In this case, the length "S4" of the transmission line is set to ¼ of the wavelength λg ₁ of the signal of frequency f ₁ (for example, 800 MHz). Also, C4
Is a signal having a frequency f ₁ and a frequency f ₂ (for example, 1.
55 GHz), a capacitor having a characteristic of passing both signals, L1 is a coil having a characteristic of being open to both signals of frequencies f ₁ and f ₂ , and D1 is a setting of a control voltage to be supplied. It is a varactor diode having a characteristic that its capacitance changes in accordance with the above, and has a characteristic of passing a signal of either frequency f ₁ or f ₂ .

In the bias circuit configured as described above, the operating frequency of the mobile phone is 800 MHz, 1.55G.
By adjusting the control voltage according to Hz,
Since the capacitance of the varactor diode D1 which is grounded changes, the frequency band of the signal to be passed can be easily changed without changing the length "S4" of the transmission line 18.

That is, the bias circuit shown in FIG.
In order to support two frequencies of 800 MHz band and 1.55 GHz band, the transmission line 18 which is a part of the components is shared for all (both) frequencies f ₁ and f ₂ , and the control voltage controls the varactor diode D1. By changing the capacitance, the other components (the coil L1, the capacitor C4, and the varactor diode D1) are configured to change their impedances according to the operating frequencies f ₁ and f ₂ (that is, this The bias circuit corresponds to the pattern B circuit).

Therefore, also in this case, the 800 MHz band,
For any signal in the 1.55 GHz band, the return loss can be minimized by maximizing the influence of the reflected wave signal, and the passing loss between the input and output can be almost eliminated. Even if a circuit having characteristics (impedance) corresponding to two frequencies of 1.55 GHz band is not separately provided, one circuit can be used for both frequencies of 800 MHz band and 1.55 GHz band by appearance. Like

As described above, according to the bias circuit in this modification, the control line is adjusted to change the capacitance of the varactor diode D1 so that the transmission line 18 commonly used for both frequencies 800 MHz and 1.55 GHz. Since it is possible to change the impedance of other components other than the above and to make the pass characteristic variable, it is possible to correspond to each of these frequencies very easily, and thus a bias circuit that can correspond to two frequency bands can be provided. It can be realized without increasing the circuit scale, and as a result, it can be sufficiently applied as a circuit for a mobile phone which requires severe conditions such as low cost and miniaturization.

Note that FIGS. 8 to 11 show the bias circuits constructed as described above, and in this case also, simulations are performed by selecting 950 MHz and 1.44 GHz as frequencies to be used near 800 MHz and 1.55 GHz, respectively. FIG. 9 is a diagram showing an example of the result in the case of 950 MHz by changing the capacitance of the varactor diode D1 by the control voltage and changing the impedance of the components other than the transmission line 18 as described above.
Each characteristic of the return loss (S11, S22) seen from the input side and the output side, which shows the best characteristic in the vicinity of z, and each passing loss (S12, S21) between the input and output (FIGS. 54 to 57).
However, as shown in FIGS. 8 to 11, 1.44 GHz
It can be seen that the characteristics have changed to the best in the vicinity.

(1-2) Description of Second Modification of Bias Circuit FIG. 12 is a diagram showing a second modification of the bias circuit described above with reference to FIG. 2. In FIG. 12, 19 is a microstrip line or the like. In this case, the length "S5" is the frequency f ₁ (for example, 800 MHz).
Is set to ¼ of the wavelength λg ₁ of the signal. Also,
C5 is a signal having a frequency f ₁ and a frequency f ₂ (for example,
A capacitor having a characteristic of passing both signals having a frequency of 1.55 GHz, L2 is a coil having a characteristic of being open to any signal of frequencies f ₁ and f ₂ , D2
Is a varactor diode having a characteristic of allowing the signal of either frequency f ₁ or f ₂ to pass by changing the capacitance according to the setting of the supplied control voltage.
Incidentally, C5 'is also a capacitor.

In the bias circuit shown in FIG. 12, a circuit including a capacitor C5 ', a coil L2 and a varactor diode D2 is connected in parallel to the transmission line 19. With such a configuration, even in the above-described bias circuit, the capacitance of the varactor diode D2 changes by adjusting the control voltage, so that the transmission line 19 other than those commonly used for both frequencies (800 MHz, 1.55 GHz) is used. Other components (capacitor C
The impedance of 5 ', the coil L2 and the varactor diode D2) changes, and as a result, the pass band of this bias circuit changes (that is, this bias circuit corresponds to the circuit of pattern B).

Therefore, also in this case, the 800 MHz band,
By adjusting the control voltage for any signal in the 1.55 GHz band, the influence of the reflected wave signal can be suppressed to the maximum and the return loss can be minimized.
Since it is possible to almost eliminate the passage loss between the input and output, it is apparent that one circuit is 800 MH, even if circuits with characteristics (impedance) corresponding to two frequencies of 800 MHz band and 1.55 GHz band are not provided individually.
It becomes possible to support both frequencies of the z band and the 1.55 GHz band.

As described above, also in the bias circuit of this modification, the control voltage is adjusted and the transmission line 1 is adjusted.
By changing the capacitance of the varactor diode D2 connected in parallel to
Since it is possible to change the impedance of other components other than the transmission line 19 commonly used for z, 1.55 GHz and make their pass characteristics variable, it is possible to correspond to each of these frequencies very easily. As a result, a bias circuit that can handle two frequency bands can be realized without increasing the circuit scale, and as a result, the bias circuit can be sufficiently applied as a circuit for a mobile phone that requires severe conditions such as low cost and downsizing. Like

13 to 16 and 17 to 20.
For the bias circuits configured as described above, the operating frequencies are 800 MHz and 1.55 in this case as well.
950 MHz and 1.
FIG. 13 is a diagram showing an example of a result when simulation is performed with 44 GHz selected. By changing the capacitance of the varactor diode D2 by the control voltage and changing the impedance of the components other than the transmission line 19 as described above, FIG. As shown in FIG. 16, each characteristic of the return loss (S11, S22) seen from the input side and the output side, which shows the best characteristic in the vicinity of 950 MHz, and each passing loss between the input and output (S12, S21) (Refer to FIGS. 54 to 57) is 1.44 GHz as shown in FIGS.
It can be seen that the characteristics change to the best in the vicinity and are optimized according to each frequency band.

(2) Description of High-Frequency Amplifier FIG. 21 is a diagram showing an example of a high-frequency amplifier used in the mobile phone described above with reference to FIG.
R1 is a field effect transistor (FE) for high frequency amplification
T), C6 are capacitors having pass characteristics for signals of frequency f ₂ (eg, 1.55 GHz), R3 is a bias setting resistor, and C6 ′ is frequency f ₁ (eg, 80).
A capacitor having a pass characteristic for a signal of 0 MHz), D3 is a varactor diode whose capacitance changes depending on the setting of the control voltage and becomes open / short circuit at frequencies f ₁ and f ₂ , and L3 is a frequency band (f ₁ , f) used. It is a coil that opens in ₂ ). In addition, G is a ground.

With the high frequency amplifier configured as described above,
Is the frequency f₂Varactor diode D when used in
Control voltage to increase the impedance of 3
When adjusting and using at frequency f1, conversely,
Control to lower the impedance of the diode D3.
By adjusting the roll voltage, each frequency f
₁, F₂The capacitance for grounding is optimized in accordance with.

That is, this high-frequency amplifier is a field effect transistor (hereinafter simply referred to as transistor) T which is a part of the components in order to correspond to the _two frequencies f ₁ and f _2.
R1 is shared for both (all) frequencies f ₁ and f ₂ , and the other components such as capacitors C6 and C6 ′, resistor R3, varactor diode D3 and coil L3 are used according to the frequencies f ₁ and f _2. Its impedance is changed (that is, this high-frequency amplifier corresponds to the circuit of pattern B).

Therefore, even in the above-mentioned high frequency amplifier, the pass characteristic can be made variable by adjusting the control voltage to change the capacitance of the varactor diode D2, so that it is extremely easy to set the two frequencies f ₁ and f ₂ . Therefore, it is possible to realize a high-frequency amplifier capable of supporting two frequency bands without increasing the circuit scale, and as a result, for a mobile phone for which severe conditions such as low cost and miniaturization are required. It can be sufficiently applied as a circuit.

The above-described high-frequency amplifier operates with one power supply, and the source of the transistor TR1 (emitter when a bipolar transistor is used) is grounded in the use frequency bands f ₁ and f ₂ to obtain a gain. Can be optimized, and the configuration shown in FIG.
It is effective for an amplifier that operates with two power supplies. (2-1) Description of First Modification of High Frequency Amplifier FIG. 22 is a diagram showing a first modification of the high frequency amplifier described above.
In FIG. 22, TR2 is a transistor for high frequency amplification (FET), TR3 and TR4 are transistors (FET) for changeover switches, C7 and C8 are DC (direct current) cut capacitors, and C9 and C10 are matching capacitors. , 20 and 21 are transmission lines each using a microstrip line or the like.

In the high-frequency amplifier shown in FIG. 22, the matching circuit composed of the capacitor C7 and the transmission line 20 and the matching circuit composed of the capacitor C8 and the transmission line 21 are composed of transistors for changeover switches (hereinafter, They are connected in parallel using TR3 and TR4 (referred to as FET switches). The FET switches TR3 and TR
ON / OFF of 4 can be simultaneously switched by a control voltage.

That is, this high-frequency amplifier is 800 MHz.
Two frequencies f ₁ and f _{2 of} z band and 1.55 GHz band
To meet the requirements, some components (transistor TR2)
There are shared as both frequencies f _1, f for _2, the other components (capacitors C9, C10), using frequency f _1,
Depending on f _2, by the switching of the ON / OFF of the FET switch TR3, TR4 by the control voltage is performed, and is configured to be connected or disconnected to the transistor TR2 (i.e., the high-frequency circuit, the pattern A Equivalent to the circuit).

With such a configuration, in the above-described high frequency amplifier, the transistors TR3 and TR4 are turned on / off.
The operating frequencies f ₁ and f ₂ are switched by switching between short circuit and open circuit of the matching circuits connected in parallel with. Therefore, as before, for the 800 MHz band, 1.55 GHz
Even if two circuits for band (high-frequency amplification transistors) are not connected in parallel, one high-frequency amplification transistor TR2 can support two frequencies, and thus can support two frequency bands. A high frequency amplifier can be realized without increasing the circuit scale, and in this case as well,
It will be applicable to mobile phone circuits that require severe conditions such as low cost and miniaturization.

(2-2) Explanation of Second Modification of High Frequency Amplifier
FIG. 23 is a diagram showing a second modification of the above-mentioned high frequency amplifier,
In FIG. 23, TR5 is a transistor for high frequency amplification
, C11, C12 are capacitors for DC cutting
C, C13, C14 are matching capacitors, D
4 and D5 are pin switches for changeover switches.
, L4 and L5 are used frequency bands f, respectively ₁, F
₂Characteristics that open at (800MHz, 1.55GHz)
Inductors (coils), 22 and 23 are respectively
It is a transmission line using a microstrip line, etc.
You.

In brief, the high frequency amplifier shown in FIG. 23 is the same as the high frequency amplifier shown in FIG.
By using the pin diodes D4 and D5 instead of the ET switches TR3 and TR4, the FET switches TR3 and T
It realizes the same function as R4. That is, this high frequency amplifier also corresponds to the circuit of pattern A. Therefore, also in this case, depending on the use frequency f _1, f2, by controlling ON / OFF of each pin diodes D4, D5 control voltage, it is possible that the pass characteristic variable,
The same effects and advantages as the first modification of the high frequency amplifier described above are obtained.

(2-3) Description of Third Modified Example of High Frequency Amplifier FIG. 24 is a diagram showing a third modified example of the above high frequency circuit. In FIG. 24, TR6 is a transistor (FET) for high frequency amplification, TR7 and TR8 are transistors (FETs) for changeover switches, C15 to C18 are capacitors for DC cut, C19 and C20 are capacitors for matching, and R4 and R5 are frequency bands f ₁ and f ₂ (800 MHz, 800 MHz, respectively). High resistance having a characteristic of opening at 1.55 GHz), and 24 and 25 are transmission lines using microstrip lines and the like, respectively.

In the high frequency amplifier shown in FIG. 24, the transistor TR6 which is a part of the components is 800
It is commonly used for both the MHz band and the 1.55 GHz band, and other components are controlled by the control voltage according to the operating frequency.
ON / OFF of TR7 and TR8
Is switched to connect or disconnect with the transistor TR6. That is,
This high frequency amplifier corresponds to the pattern A circuit.

With such a configuration, in the above high frequency amplifier, each FET switch TR is controlled by the control voltage.
When 7 and TR8 are set to the ON state, the capacitors C16 and C17, the high resistances R4 and R5, and the FET switches TR7 and TR8 are connected to the amplifying transistor TR6, respectively, and the matching circuit (the capacitor C19 or the capacitor C20). The phase of the signal up to
Since it is delayed compared with the case of transmitting 25, the circuit becomes a circuit in which the phase of the signal is delayed.

On the other hand, when each FET switch TR7, TR8 is set to the OFF state by the control voltage,
Capacitor C16, C17, high resistance R4, R respectively
5, the FET switches TR7 and TR8 are separated from the amplifying transistor TR6, and the signal is transmitted through the transmission lines 24 and 25, so that the phase of the signal advances.

As a result, as described above, the used frequencies f ₁ and f
ON / OF of FET switches TR7 and TR8 depending on ₂
800MH by changing the phase of the signal by F
Since it becomes possible to select the optimum passing phase for each frequency of the z band and the 1.55 GHz band, in this case as well, two circuits for the 800 MHz band and the 1.55 GHz band (for high frequency amplification) are used as before. Even if transistors are not connected in parallel, one high frequency amplification transistor TR6 can handle these two frequencies.

Therefore, a high-frequency amplifier capable of supporting these two frequency bands can be realized while minimizing the circuit scale, and can be sufficiently applied as a circuit for a mobile phone which requires severe conditions such as low cost and downsizing. Like (2-4) Description of Fourth Modification of High Frequency Amplifier FIG. 25 is a diagram showing a fourth modification of the high frequency amplifier described above.
In FIG. 25, TR9 is a transistor for high frequency amplification, C21 to C24 are capacitors for cutting DC, and C2.
5, C26 are matching capacitors, D6 and D7 are pin diodes for changeover switches, R6 and R, respectively.
7 are used frequencies f ₁ and f ₂ (800 MHz,
High resistance, L with the characteristic of being open at 1.55 GHz)
Reference numerals 6 and L7 are inductors (coils) each having a characteristic of being open in the frequency band used, and reference numerals 26 and 27 are transmission lines using microstrip lines or the like.

That is, the high frequency amplifier shown in FIG. 25 has pin diodes D instead of the FET switches TR7 and TR8 in the high frequency amplifier shown in FIG.
By using 6, D7, each FET switch TR
7, the same function as TR8 is realized. That is, this high frequency amplifier corresponds to the circuit of pattern A.

Therefore, even in this high frequency amplifier, the ON / OFF states of the pin diodes D6 and D7 are controlled by the control voltage according to the used frequencies f ₁ and f ₂ , so that the frequencies of 800 MHz band and 1.55 GHz band can be obtained. Since the optimum passing phase can be selected, there are the same effects or advantages as the high frequency amplifier described in the third modification.

(2-5) Description of Fifth Modification of High Frequency Amplifier FIG. 26 is a diagram showing a fifth modification of the high frequency amplifier described above.
In FIG. 26, TR10 is a transistor (FET) for high frequency amplification, 28 is a demultiplexing circuit, 29 and 30 are matching circuits respectively, and 31 is a multiplexing circuit. As shown in FIG. 800MHz band, 1.55G
In order to correspond to the (Hz band), two matching circuits 29 and 30 are connected via the branching circuit 28 and the synthesizing circuit 31, respectively (that is, this high-frequency amplifier corresponds to the circuit of pattern C).

Here, the demultiplexing circuit 28 demultiplexes the input signal, and has a characteristic that the signals are opened to each other for signals in the 800 MHz band and the 1.55 GHz band.
As a result, the matching circuits 29 and 30 are not affected, so that one transistor TR10 can amplify two types of frequencies. Therefore, in this case as well, 2
A high-frequency amplifier that can handle various frequency bands can be realized while minimizing the circuit scale, and similarly, it can be sufficiently applied as a circuit for mobile phones that require severe conditions such as low cost and miniaturization. .

(3) Description of Directional Coupler FIG. 27 is a block diagram showing the configuration of the directional coupler used in the mobile phone described above with reference to FIG. 1. In FIG. 27, reference numerals 32 to 34 denote microstrip lines. The transmission line 34 has a length "S6" of two frequencies (800 MHz, 1.55 GH).
The wavelength λg of the higher signal (1.55 GHz) of z)
_It is set to 1/4 of ₂ and the length of the transmission line 33 "S
7 ”is the one with lower frequency of“ S6 + S7 ”(800MH
It is set to be ¼ of the wavelength λg ₁ of the signal z).

Further, R8 and R9 are terminating resistors, and 35 is a used frequency (800 MHz, 1.55 GH).
z) is a high frequency switch (RF switch) for switching the connection of the transmission line 34 to the transmission line 33 or the terminating resistor R8. The RF switch 35 is 800M
When used in the Hz band, it is switched to the transmission line 33 side, and when used in the 1.55 GHz band, the terminating resistor R8.
It can be switched to the side.

That is, the directional coupler shown in FIG. 27 is a component of the transmission line 3 in order to support two frequencies of 800 MHz band and 1.55 GHz band.
4 is shared for both (all) frequencies, and the transmission line 33, which is another component, corresponds to the transmission frequency 3 depending on the frequency used.
4 is connected or disconnected (that is, this directional coupler corresponds to the circuit of pattern A).

With such a configuration, in the above-mentioned directional coupler, the transmission line 3 is switched by switching the RF switch 35.
By adjusting the amount of coupling with 2 to the used frequency band of either the 800 MHz band or the 1.55 GHz band, the optimum degree of coupling for the used frequency band can be obtained. Therefore, one directional coupler can handle two kinds of frequencies without connecting two directional couplers for 800 MHz band and 1.55 GHz band in parallel as in the conventional case. As a result, it is possible to realize a high-frequency amplifier compatible with both the 800 MHz band and the 1.55 GHz band without increasing the circuit scale, and as a result, as a circuit for a mobile phone, which requires severe conditions such as low cost and downsizing. It will be applicable enough.

(4) Description of High-Frequency Filter Circuit FIG. 28 is a diagram showing an example of a dual-band compatible high-frequency filter circuit used in the mobile phone described above with reference to FIG. 1. In FIG. 28, 40 is a signal line having an inductance. (Inductor), 41, 42 are dielectric resonators (D
R) and C31 to C35 are capacitors. In addition, G is a ground.

The high frequency filter circuit shown in FIG. 28 has a two-stage structure of a filter circuit having a unit structure using the dielectric resonators 41 and 42, and an inductor 40 is provided between these two-stage structure circuits. By being connected, mutual phase adjustment is performed. Here, the procedure for configuring the high-frequency filter circuit having the above-described unit configuration will be described in detail below with reference to FIGS. 29 (a) to 29 (d).

First, assuming that the length of the dielectric resonator 41 'for passing or attenuating a certain resonance frequency f ₁ (for example, 800 MHz) is L ₁ as shown in FIG. As shown in FIG. 29 (b), an arbitrary frequency f ₂ higher than the resonance frequency f ₁ thereof (for example, 1.55G
The dielectric resonator 41 for passing or attenuating (Hz) is constructed so that its length is L ₂ . At this time, the lengths L ₁ and L ₂ of the dielectric resonators 41 ′ and 41 are configured such that L ₂ <L ₁ .

Further, as shown in FIG. 29C, the length L _{3 is} such that the sum of the lengths of the dielectric resonator 41 and the dielectric resonator 41 'is the same as the length L _1. 29 is added (that is, L ₁ = L ₂ + L ₃ ), and FIG.
As shown in (d), a capacitor C31 (C33) is connected to the connection point of the dielectric resonators 41 and 42, and
The capacitor C32 (C34) is connected to the dielectric resonator 42.

At this time, each capacitor C31,
The constants of C32 (C33, C34) depend on the resonance frequencies f ₁ and f ₂ , respectively, and the capacitor C31 is set with a constant that makes the signal near the frequency f ₂ close to a short circuit. The capacitor C32 has a frequency f ₁
A constant is set so that it becomes close to a short circuit with respect to a nearby signal. The capacitors C31, C32 (C3
3, C34) are in an irrelevant (open: open) state with respect to the mutual resonance frequencies f ₁ and f ₂ .

By the above procedure, the unit component part of the high frequency filter circuit shown in FIG. 28 is constructed. Then, in the high frequency filter circuit configured as described above,
Since the signal of the resonance frequency f ₂ flows into the capacitor C31 so that the phase is different by 90 ° between both ends of the dielectric resonator 41,
One end of the dielectric resonator 41 is short-circuited and the other end is open, and the dielectric resonator 42 is separated from the dielectric resonator 41. On the other hand, the signal of the resonance frequency f ₁ flows to the capacitor C32 (C33) so that the phases are different by 90 ° at both ends when the dielectric resonator 41 and the dielectric resonator 42 are regarded as one dielectric resonator. As a result, when the dielectric resonator 41 and the dielectric resonator 42 are regarded as one dielectric resonator, one end thereof is short-circuited and the other end thereof is open, and the dielectric resonator 42 is dielectrically resonant. It is in a state of being connected to the container 41.

That is, in this high frequency filter circuit, the dielectric resonator 41 which is a part of the components is shared for both (all) frequencies so as to correspond to the _two frequencies f ₁ and f ₂ , and other frequencies are used. The dielectric resonator 42 and the capacitor C32 (C34), which are the constituent elements, are connected to or disconnected from the dielectric resonator 41 according to the frequency used (that is, this high-frequency filter circuit has a pattern A pattern). Equivalent to the circuit).

In this case, when the dielectric resonator 42 and the capacitor C32 (C34) are separated from the dielectric resonator 41, the portion composed of the dielectric resonator 41 and the capacitor C31 (C33) is removed. It becomes a filter circuit for the frequency f ₂ , and the dielectric resonator 41 is connected to the dielectric resonator 4
2, when the capacitor C32 (C34) is connected, the dielectric resonators 41 and 42 and the capacitor C32
The portion composed of (C34) serves as a filter circuit for the frequency f ₁ .

As described above, according to the above high frequency filter circuit, the same length L ₁ = L ₂ + as that of the dielectric resonator 41 ′ for the frequency f ₁ (800 MHz) [see FIG. 29 (a)].
By using the dielectric resonators 41 and 42 which are L ₃ , the dielectric resonator 41 is commonly used for frequency,
Capacitor C32 (C34) is used frequency f _1, f
₂ (800 MHz, 1.55 GHz) by connecting or disconnecting with the dielectric resonator 41,
Since both frequencies f ₁ and f ₂ can be supported,
Without increasing the circuit scale, 800MHz band,
It is possible to realize a high frequency filter circuit for a mobile phone that can handle both frequencies in the 1.55 GHz band.

When the dielectric resonator 42 and the capacitor C32 are separated from the dielectric resonator 41 as described above, the passing characteristic of a signal having a frequency near the frequency f ₂ is only the constant of the capacitor C31. In the state where the dielectric resonator 42 and the capacitor C32 are connected to the dielectric resonator 41, the pass characteristic of a signal having a frequency near the frequency f ₁ depends only on the constant of the capacitor C31. Become.

Therefore, for example, the capacitors C31 and C3
When the constants of 3 are changed, the pass characteristic near the frequency f ₂ can be changed as shown by the broken line in FIG. 30 (a), and when the constants of the capacitors C32 and C34 are changed, FIG. ), It is possible to change the pass characteristic in the vicinity of the frequency f ₁ , so that the dielectric resonator (microstrip line) 41,
It is not necessary to finely adjust the frequencies f ₁ and f ₂ after the configuration by cutting 42, and each of the capacitors C31 to C32
Fine adjustment of the pass characteristic can be performed very easily only by adjusting each of the constants independently.

FIG. 31 shows the operating frequency band of the above-mentioned high frequency filter circuit of 950 MHz band and 1.44 GH.
FIG. 32 is a diagram showing an example of a configuration for performing simulation in the z band. As shown in FIG. 31, terminating resistors 43 and 44 are connected to the input side and the output side, respectively. 32 (a) and 32 (b) are diagrams showing an example of the simulation result.

Then, as shown by M1 and M2 in FIG. 32 (a), the above-mentioned high-frequency filter circuit focuses on a pass band of a certain band (950 MHz band, 1.44 GHz band), which is 950 MHz band, 1 While having a frequency characteristic (S21) as a BPF (band pass filter) that passes each band of the .44 GHz band, as shown by M3 and M4, if only the attenuation pole is focused, the 950 MHz band, 1.44
This means that it has frequency characteristics as a BEF (band attenuation filter) that attenuates each band in the GHz band. That is, it can be said that this high-frequency filter circuit is a circuit having characteristics of both BPF and BEF.

Further, as indicated by M1 and M2 in FIG. 32 (b), the high frequency filter circuit described above has a frequency of 950 MHz.
It can be seen that sufficiently good characteristics are obtained as a dual-band filter circuit that can handle both the band and the 1.44 GHz band. (4-1) Description of First Modification of High-Frequency Filter Circuit FIG. 33 is a diagram showing a first modification of the above-described high-frequency filter circuit. In FIG. 33, the same reference numerals as those shown in FIGS. 28 and 31 are used. The portions indicated by are the same as those described above with reference to FIGS. 28 and 31, respectively, but in the present modification, the dielectric resonator 41 is divided into dielectric resonators 41A and 41B, respectively. 41A, 41B, 42 are configured to have different impedances.

In other words, this high frequency filter circuit also has 80
Two frequencies of 0MHz and 1.55GHz (f ₁ ,
In order to correspond to f ₂ ), some of the dielectric resonators 41A and 41B, which are the constituent elements, are shared for both (all) frequencies, and the dielectric resonator 42 and the capacitor C32 (C34, which are the other constituent elements). ) Is connected to or disconnected from the dielectric resonators 41A and 41B according to the frequency used (that is, this high-frequency circuit also corresponds to the circuit of pattern A).

Therefore, the high frequency filter circuit shown in FIG. 33 can also support both the 800 MHz band and the 1.55 GHz frequency band as in the circuits described above with reference to FIGS. 28 and 31, but in this case. Because the dielectric resonator 41 is divided into two dielectric resonators 41A and 41B, the resonance frequency f ₁ has higher selectivity, that is, signals of frequencies f ₁ and f ₂ are higher. Only will be able to pass or be attenuated.

FIGS. 34 (a) and 34 (b) show the frequency bands used in the 950 MHz band, 1.
FIG. 34A is a diagram showing an example of a result obtained when simulation is performed in the 44 GHz band.
As shown in (b), 950 MHz band, 1.44 GHz
Since the sharpness of both the pass characteristic (S21) and the attenuation characteristic (S11) in the band is higher than that shown in FIG. 32 (a), the high frequencies f ₁ and f ₂ as described above are obtained.
It can be seen that the selectivity of is obtained.

(4-2) Description of Second Modification of High Frequency Filter Circuit FIG. 35 is a diagram showing a second modification of the high frequency filter circuit described above with reference to FIGS. 28 and 31, and in FIG.
28 and 31 are the same as those described above with reference to FIGS. 28 and 31, respectively, but the high-frequency circuit shown in FIG. 35 is similar to that shown in FIGS. In the configuration shown in, each capacitor C31 (C3
3) and C32 (C34) are replaced with circuits using varactor diodes 45 and 46, respectively. C36 and C37 are capacitors and 4 respectively.
Reference numerals 3 and 44 are inductors (coils). The circuit shown in FIG. 35 shows only a unit component.

That is, the high frequency filter circuit described above is
Two frequencies f of 00MHz and 1.55GHz₁,
f₂In order to support the
Is shared for both (all) frequencies,
Voltage (control voltage) V ₁, V₂By each rose
Frequency of the diode 45, 46 (other components)
Number f₁, F₂Its impedance is changed according to
(That is, this high frequency filter circuit
Corresponds to the circuit of pattern B).

Therefore, in this high-frequency circuit, the corresponding frequencies are easily changed by changing the resonance frequencies f ₁ and f ₂ resonating in the dielectric resonators 41 and 42 by the control voltages V ₁ and V ₂ . In this case as well, it is possible to achieve 800 without increasing the circuit scale.
It is possible to realize a high frequency filter circuit for a mobile phone that can handle both frequencies of the MHz band and the 1.55 GHz band.

(4-3) Description of Third Modification of High Frequency Filter Circuit FIG. 36 is a diagram showing a third modification of the high frequency filter circuit described above with reference to FIGS. 28 and 31, and in FIG. 36 as well.
28 and 31 are the same as those described above with reference to FIGS. 28 and 31, respectively, but the circuit shown in FIG. 36 (circuit of unit configuration)
Is provided with a switch (SW) 46 so that the dielectric resonator 41 and the dielectric resonator 42 or the capacitor C3.
The connection with 1 can be switched.

That is, this high frequency filter circuit is
Two frequencies f ₁ and f of 0 MHz and 1.55 GHz
Dielectric resonator 41 (some components) to support ₂
Is shared for both (all) frequencies f ₁ and f ₂ ,
Other components of the dielectric resonator 42, the capacitor C32 (C34), or the capacitor C31 (C33) are configured to be connected to or disconnected from the dielectric resonator 41 according to the operating frequencies f ₁ and f ₂ . (That is, this high frequency filter circuit corresponds to the circuit of pattern A).

As a result, in the high frequency filter circuit described above,
Is the operating frequency f₁, F₂Switch 46 according to
By changing the frequency band (frequency
Number f ₁Band, frequency f₂So that you can change the obi)
Become. Therefore, as in the conventional case, for the 800 MHz band, 1.
Connect two dielectric resonators for 55 GHz band in parallel
It is not necessary to support the frequency band of
As a road, a dual that has reduced the circuit scale and cost
It is possible to realize a high-frequency filter circuit that supports rubands.
Wear.

(4-4) Description of Fourth Modification of High Frequency Filter Circuit FIG. 37 is a diagram showing a fourth modification of the high frequency filter circuit described above with reference to FIGS. 28 and 31, and in FIG.
The components denoted by the same reference numerals as those in FIGS. 28 and 31 are the same as those described above with reference to FIGS. 28 and 31, respectively, but the high-frequency filter circuit (unit component portion) shown in FIG. The switch 46 described above in the third modification.
The connection switching operation is performed by controlling ON / OFF of the pin diode 47 by the control voltage V ₃ (that is, this high frequency filter circuit also corresponds to the pattern A circuit). Incidentally, 48 is an inductor (coil), and 49 is a resistor.

Therefore, in this high frequency circuit, the pin diode 47 is turned ON / OFF according to the used frequencies f ₁ and f _2.
By controlling the control voltage V ₃ with the control voltage V ₃ , the corresponding frequency band can be instantaneously changed in the same manner as described above in the third modification. It is not necessary to connect two dielectric resonators for the band and the 1.55 GHz band in parallel to support both frequency bands, and it is a dual-band compatible circuit that is sufficiently small as a circuit for mobile phones and has a reduced cost. The high frequency filter circuit can be realized.

(4-5) Description of Fifth Modification of High Frequency Filter Circuit FIG. 38 is a diagram showing a fifth modification of the high frequency filter circuit described above with reference to FIGS. 28 and 31, and in FIG.
The components denoted by the same reference numerals as those in FIGS. 28 and 31 are the same as those described above with reference to FIGS. 28 and 31, respectively, but the high-frequency filter circuit (unit constituent portion) shown in FIG. The pin diode 5 is provided between the connection point of the dielectric resonators 41 and 42 and the capacitor C31 (C33).
0 is provided and ON / OFF of the pin diode 50 is controlled by the control voltage V ₄ to perform the switching operation of the switch 46 described above in the third modification (that is, this high frequency filter circuit). Also corresponds to the circuit of pattern A). Note that 52 and 52 are inductors (coils), and 53 is a resistor.

Therefore, even in this high frequency circuit, the pin diode 50 is turned on / off in accordance with the used frequencies f ₁ and f _2.
By controlling the control voltage V ₄ with the control voltage V ₄ , it becomes possible to instantly change the corresponding frequency band in the same manner as described in the third modification. It is not necessary to connect two dielectric resonators for the band and the 1.55 GHz band in parallel to support both frequency bands, and it is a dual-band compatible circuit that is sufficiently small as a circuit for mobile phones and has a reduced cost. The high frequency filter circuit can be realized.

(5) Description of Voltage Controlled Oscillator FIG. 39 (a) is a diagram showing an example of the configuration of the voltage controlled oscillator used in the portable telephone described above with reference to FIG.
In FIG. 9A, reference numeral 61 is a resonance circuit section, 62 is an oscillation circuit section, and the resonance circuit section 61 includes a coil (L) 63, a variable capacitance diode (varactor diode: D) 64, capacitors (C) 65, 69. , 70, a high frequency switch (SW1) 67 and strip lines 66 and 68, and the oscillation circuit section 62 is an application of a so-called Colpitts type oscillation circuit, and capacitors (C) 71 to 7 are provided.
6, a high frequency switch (SW2) 77, a transistor (TR) 78 and a coil (L) 79. Reference numeral 80 is a resonance circuit including a capacitor 75 and a coil 79.

Further, this voltage controlled oscillator has two kinds of frequencies (80
It is a dual band oscillator that can oscillate at 0 MHz and 1.55 GHz. Hereinafter, the main part of this voltage controlled oscillator will be described in detail. First, as shown in FIG. 40 (a), the lengths of the respective microstrip lines (hereinafter simply referred to as striplines) 66, 68 of the resonance circuit section 61 shown in FIG. 39 are set to L ₄ and L ₅ , respectively. By switching the switch 67 to the side of the capacitor 69, the strip line 66 having the length L ₄ has two frequencies f ₁ and f ₂ (80
40 MHz by switching the switch 67 to the strip line 68 side in response to the higher resonance frequency f ₂ (1.55 GHz) of 0 MHz and 1.55 GHz.
As shown in (c), the strip line of length L ₄ + L ₅ to which the strip lines 66 and 68 are connected is configured to correspond to the lower resonance frequency f ₁ (800 MHz).

That is, the above-mentioned circuit (high frequency circuit) is
In order to support two frequencies of 00 MHz and 1.55 GHz, the strip line 66 (some components) is shared for both (all) frequencies f ₁ and f ₂ , and the other components (strip line 68, The capacitor 69) changes the strip line 66 according to the used frequencies f ₁ and f _2.
Are connected or disconnected (that is, this circuit corresponds to the pattern A circuit).

In addition, the capacitor 69 connected to the strip line 66 has a constant that causes an AC (alternating current) short with respect to the resonance frequency f ₂ (the strip line 66 having the length L ₄ ). On the other hand, a constant is set in the capacitor 70 connected to the strip line 68 so as to be AC short-circuited with respect to the resonance frequency f ₁ (strip line of length L ₄ + L ₅ ). . The capacitors 69 and 70 are in an unrelated (open) state with respect to the resonance frequencies f ₁ and f ₂ of each other.

With such a configuration, in the above-mentioned resonance circuit section 61, when the switch 67 is switched to the capacitor 69 side, the resonance frequency becomes f ₁ , and when the switch 67 is switched to the microstrip line 68 side, the resonance frequency is f. _{Since it is 2} , different frequency bands (8
The oscillation frequency can be instantly changed to the 00 MHz band or the 1.55 GHz band.

41 (a) and 41 (b) are respectively shown in FIG.
For the circuit shown in (a), the operating frequency is 950 MHz.
FIG. 3 is a diagram showing an example of the result when the simulation is performed at z, 1.44 GHz, and M in each of these diagrams.
As shown by 1 to M4, it is understood that the frequency characteristic of the circuit shown in FIG. 40 (a) can cope with both near 950 MHz and 1.44 GHz.

On the other hand, in the oscillation circuit section 62 shown in FIG. 39,
As described above, in the resonance circuit section 61, different oscillation frequencies (resonance frequencies) f ₁ and f ₂ are switched to oscillate, so that it is necessary to generate a negative resistance according to this. However, if the oscillation circuit unit 62 is, for example, 800 MHz
These negative resonance frequencies f are generated by generating a negative resistance capable of covering a wide frequency band of z to 1.55 GHz.
_{If 1} and f ₂ are covered, oscillation may occur at frequencies other than these resonance frequencies f ₁ and f ₂ , and unnecessary spurious may occur.

Therefore, the voltage-controlled oscillation in this embodiment is performed.
The resonance frequency band f₁, F ₂And narrow band negative resistance
In order to generate the resistance, as shown in FIG. 39 and FIG.
The grounded collector of the transistor 78 of the oscillation circuit unit 62
And each resonance frequency f₁, F₂Resonant circuit 80 corresponding to
By providing, each resonance frequency f₁, F₂Narrow belt corresponding to
It produces a wide range of negative resistance.

At this time, the oscillation circuit section 62 needs to be adjusted or switched in order to generate the negative resistances corresponding to the resonance frequencies f ₁ and f ₂ switched by the resonance circuit section 61. In the embodiment, FIG. 39 and FIG.
As shown in FIG. 3, two capacitors 73 and 74, which are grounded in parallel to the feedback part of the transistor 78, are connected in parallel via a switch [AC (alternating current) switch] 77,
By switching the switch 77, the negative resistance band can be instantaneously changed.

That is, the circuit shown in FIG. 43 (high frequency circuit)
Also has two frequencies f ₁ and f ₂ (800 MHz, 1.55
GHz), the transistor 78, the resonance circuit 8
Some components such as 0 are shared for both frequencies f ₁ and f ₂ , and other components of the capacitors 73 and 74 depend on the used frequencies f ₁ and f ₂ and some of the components described above. Are connected to or disconnected from each other (that is, this circuit also corresponds to the pattern A circuit).

Therefore, the switch 67 in the resonance circuit 61 is
Resonance frequency f by switching₁, F ₂Depending on the transition of
By switching the switch 77, the resonance circuit section 6
Resonance frequency f at 1₁, F₂Can respond to
It becomes possible to obtain a fixed oscillation. Note that FIG.
4 (a) and 4 (b) are as shown in FIGS. 42 and 43, respectively.
Does not provide a resonance circuit 80 that generates a negative resistance in a narrow band
Circuit used frequency 950MHz, 1.55GH
An example of the result when simulation is performed as z
FIG. 45 (a) and FIG. 45 (b) are both
A similar simulation for the circuit provided with the vibration circuit 80.
It is a figure which shows an example of the result at the time of performing a switch.

Each of these FIG. 44 (a), (b) and FIG.
As shown in (a) and (b), the resonance circuit 80 is not provided.
If you want to oscillate a frequency near M1 in the figure,
Unwanted sp that also oscillates frequencies near M2
If a resonance occurs and the resonance circuit 80 is installed,
It can be seen that no unnecessary spurious is generated. As above
In addition, according to the voltage controlled oscillator of the present embodiment,
The switches 67 and 77 are attached to the circuit section 61 and the oscillation circuit section 62, respectively.
Provide and use frequency f₁, F₂Each of these depending on
Oscillation frequency f by switching the switches 67 and 77.
₁, F₂66 and 6 can be switched.
As shown in 7, the frequency f ₁For frequency f₂Two for
Voltage controlled oscillators 134A, 134B, or VCO
No need to connect modules 135A and 135B in parallel
In addition, the circuit scale can be minimized.

Therefore, the present invention greatly contributes to the realization of a voltage control oscillator compatible with a dual band, which can be sufficiently applied to a mobile phone and the like which are required to be downsized and low cost. (5-1) Description of Modification of Voltage Controlled Oscillator FIG. 46 shows the resonance circuit section 61 described above with reference to FIGS. 39 and 40.
FIG. 46 is a diagram showing a modified example of the main part of FIG. 46. In the circuit shown in FIG. 46, the switching operation by the switch (SW1) 67 shown in FIGS. 39 and 40 is performed by the pin diode (D) at the control voltages V ₅ and V _6. This is realized by switching ON / OFF of 84 and 85 (thus, this circuit also corresponds to the pattern A circuit). Reference numeral 81 is a capacitor (C), and reference numerals 82 and 83 are coils (L).

Therefore, also in the circuit shown in FIG. 46, the control voltages V ₅ and V ₅ are set in accordance with the operating frequencies f ₁ and f _2.
ON / OFF of each pin diode 84, 85 by ₆
The resonance frequency (oscillation frequency) f
Can be switched between ₁ and f ₂ , 800MHz
It becomes possible to easily cope with frequency bands far apart from each other, such as the band and the 1.55 GHz band.

Incidentally, as shown in FIGS. 47 (a) and 47 (b), the structure of the main part of the resonance circuit portion 61 has a structure corresponding to the circuit of the above-mentioned pattern A and is a variable capacitance diode (varactor diode). Even if the varactor diodes 64A and 64B having mutually different capacitances are connected in parallel through the switch (SW1) 67 instead of 64, the resonance frequencies f ₁ and f are instantaneously changed by switching the switch (SW1) 67. ₂ switching (transition) can be performed. In this case, the interval between the resonant frequencies f ₁ and f ₂ at which the transition is possible becomes narrower than that shown in FIGS. 39 and 40.

Similarly, the structure of the main part of the resonance circuit 61 is, as shown in FIGS. 48 (a) and 48 (b), in the structure corresponding to the circuit of pattern A, the varactor diodes 64A having different capacitances. , 64B (varactor diode 64A) in the opposite direction to the RF line (signal line)
Connected in parallel with each other and applying a positive (+) / negative (-) bias voltage to the switch (SW3) 88 to switch the switch 88, the resonance frequencies f ₁ and f ₂ are switched instantaneously ( Transition) can be performed. In this case as well, the resonance frequency interval at which transition can be performed becomes narrower than that shown in FIGS. 39 and 40.

Next, FIG. 49 is a diagram showing a modified example of the main part of the oscillation circuit section 62 described above with reference to FIGS. 39 and 43.
The circuit shown in FIG. 46 is configured by replacing the switch (SW2) 77 for switching between the capacitors 73 and 74 in the negative resistance band shown in FIGS. 39 and 43 with a pin diode 86 (that is, this circuit also. It corresponds to the circuit of pattern A).

Therefore, also in this case, depending on the resonance frequencies f ₁ and f ₂ in the resonance circuit portion 61, ON / OFF of the pin diode 86 is switched by setting the control voltage V ₇ applied to the pin diode 86. As a result, stable oscillation can be performed corresponding to the resonance frequencies f ₁ and f ₂ . Now, hereinafter, a method of adjusting the resonance frequency of the resonance circuit unit 61 as described above will be described in detail.

50 (a) and 50 (b) are schematic views showing an example of the case where the resonance circuit portion 61 is formed on a substrate. In each of FIGS. 50 (a) and 50 (b), 91 is A substrate, 92 is an RF line (high-frequency signal line), 93 is a ground (GND) surface, 94 is an open stub for adjusting resonance frequency, 95A and 95B are through holes, and 96 is an inner layer of the substrate 91. As shown in FIG. 50B, the adjustment open stub 94 is a strip line resonator, and the adjustment open stub 94 is provided through the through hole 95B.
1 is formed on the surface. The adjustment open stub 94 used is sufficiently thinner than the stripline resonator 96.

As a result, the stripline resonator 96
Although it is arranged on the inner layer of the substrate 91, the resonance frequency of the stripline resonator 96 can be adjusted very easily by simply cutting the adjustment open stub 94. After mounting the circuit,
Since the stripline resonator 96 is inserted as an inner layer in the substrate 91, the stripline resonator 96 cannot be trimmed directly and the resonance frequency cannot be finely adjusted.

Next, FIG. 51A shows a substrate 9 in which the above-described stripline resonator 96 is formed on the substrate 91.
51 is a sectional view of FIG. 1, and FIG. 51 (b) is A in FIG. 51 (a).
51 (c) is the same as FIG. 51 (a).
As shown in FIG. 51 (c), in this case, as shown in FIG. 51 (c), a resonance frequency adjusting groove 97 is formed on the back surface (ground surface 92) of the substrate.

Here, in a distributed constant circuit such as the resonance circuit section 61, usually, the change of the ground pattern of the ground plane 92 is equal to the change of the circuit constant. Therefore, if the ground pattern is changed by cutting the adjustment groove 97 formed on the ground (GND) surface 92, the resonance frequency of the stripline resonator 96 can be adjusted very easily. .

Each high-frequency circuit (high-frequency amplifier, high-frequency filter circuit, directional coupler, voltage-controlled oscillator having a configuration corresponding to any one of patterns A to C) in this embodiment is a mobile phone. 800MHz for the corresponding frequency band to be applied as a circuit for
Although two frequency bands, z band and 1.55 GHz band, are used, the high frequency circuit of the present invention is not limited to this, and can be applied to a wireless device other than a mobile phone.
It can also support multiple frequency bands other than the MHz band and the 1.55 GHz band.

[0129]

As described in detail above, according to the high frequency circuit of the present invention as defined in claims 1 and 2, some components are shared for all frequencies, and other components are
Depending on the frequency used, it will be connected or disconnected to some of these components, or the impedance can be changed according to the frequency used,
A single circuit can handle a plurality of frequencies without individually providing circuits corresponding to a plurality of frequencies, thereby increasing the circuit scale and cost of a high-frequency circuit capable of handling a plurality of frequencies. There is an advantage that it can be realized very easily.

Further, according to the high frequency circuit of the present invention as defined in claim 3, since a plurality of matching circuits are provided and these matching circuits are respectively connected through the demultiplexing / combining circuit, what frequency is used? Since it is possible to always match the circuit even with a signal having a frequency, one high-frequency circuit can handle a plurality of frequencies, and thus a high-frequency circuit that can handle a plurality of frequencies ， It has the advantage that it can be realized without increasing the cost.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a configuration of a mobile phone to which a high frequency circuit according to an embodiment of the present invention is applied.

FIG. 2 is a diagram showing a configuration of a bias circuit used in a high frequency amplifier in the mobile phone of the present embodiment.

FIG. 3 is a diagram showing an example of a simulation result of a bias circuit according to the present embodiment.

FIG. 4 is a diagram showing an example of a simulation result of a bias circuit in the present embodiment.

FIG. 5 is a diagram showing an example of a simulation result of the bias circuit according to the present embodiment.

FIG. 6 is a diagram showing an example of a simulation result of the bias circuit according to the present embodiment.

FIG. 7 is a diagram showing a first modification of the bias circuit according to the present embodiment.

FIG. 8 is a diagram showing an example of a simulation result of a bias circuit as a first modified example of the present embodiment.

FIG. 9 is a diagram showing an example of a simulation result of a bias circuit as a first modified example of the present embodiment.

FIG. 10 is a diagram showing an example of a simulation result of a bias circuit as a first modified example of the present embodiment.

FIG. 11 is a diagram showing an example of a simulation result of a bias circuit as a first modified example of the present embodiment.

FIG. 12 is a diagram showing a second modification of the bias circuit according to the present embodiment.

FIG. 13 is a diagram showing an example of a simulation result of a bias circuit as a second modified example of the present embodiment.

FIG. 14 is a diagram showing an example of a simulation result of a bias circuit as a second modified example of the present embodiment.

FIG. 15 is a diagram showing an example of a simulation result of a bias circuit as a second modified example of the present embodiment.

FIG. 16 is a diagram showing an example of a simulation result of a bias circuit as a second modified example of the present embodiment.

FIG. 17 is a diagram showing an example of a simulation result of a bias circuit as a second modified example of the present embodiment.

FIG. 18 is a diagram showing an example of a simulation result of a bias circuit as a second modified example of the present embodiment.

FIG. 19 is a diagram showing an example of a simulation result of a bias circuit as a second modified example of the present embodiment.

FIG. 20 is a diagram showing an example of a simulation result of a bias circuit as a second modified example of the present embodiment.

FIG. 21 is a diagram showing a configuration of a high frequency amplifier according to the present embodiment.

FIG. 22 is a diagram showing a first modification of the high-frequency amplifier according to this embodiment.

FIG. 23 is a diagram showing a second modification of the high-frequency amplifier according to this embodiment.

FIG. 24 is a diagram showing a third modification of the high-frequency amplifier according to this embodiment.

FIG. 25 is a diagram showing a fourth modification of the high-frequency amplifier according to this embodiment.

FIG. 26 is a diagram showing a fifth modification of the high-frequency amplifier according to this embodiment.

FIG. 27 is a diagram showing a configuration of a directional coupler according to the present embodiment.

FIG. 28 is a diagram showing a configuration of a high frequency filter circuit according to the present embodiment.

29 (a) to 29 (d) are diagrams for explaining a configuration procedure of the high-frequency filter circuit according to the present embodiment.

30A and 30B are diagrams for explaining the operation of the high-frequency filter circuit according to the present embodiment.

FIG. 31 is a diagram showing a configuration of the high-frequency filter circuit according to the present embodiment at the time of simulation.

32A and 32B are diagrams showing an example of simulation results of the high-frequency filter circuit according to the present embodiment.

FIG. 33 is a diagram showing a first modification of the high-frequency filter circuit according to this embodiment.

FIG. 34 is a diagram showing an example of a simulation result of a high-frequency filter circuit as a first modified example of the present embodiment.

FIG. 35 is a diagram showing a second modification of the high-frequency filter circuit according to this embodiment.

FIG. 36 is a diagram showing a third modification of the high-frequency filter circuit according to this embodiment.

FIG. 37 is a diagram showing a fourth modification of the high-frequency filter circuit according to this embodiment.

FIG. 38 is a diagram showing a fifth modification of the high-frequency filter circuit according to the present embodiment.

FIG. 39 is a diagram showing a configuration of a voltage controlled oscillator according to the present embodiment.

40 (a) to (c) are diagrams showing a configuration of a main part of a resonance circuit unit of the voltage controlled oscillator according to the present embodiment.

41A and 41B are diagrams showing an example of a simulation result of the voltage controlled oscillator according to the present embodiment.

FIG. 42 is a diagram showing a configuration of a main part of an oscillation circuit unit of the voltage controlled oscillator according to the present embodiment.

FIG. 43 is a diagram showing a configuration of a main part of an oscillation circuit unit of the voltage controlled oscillator according to the present embodiment.

FIGS. 44 (a) and 44 (b) are diagrams showing an example of simulation results for comparing and explaining the frequency characteristics of the voltage controlled oscillator according to the present embodiment.

45 (a) and 45 (b) are diagrams showing an example of a simulation result of the voltage controlled oscillator according to the present embodiment.

FIG. 46 is a diagram showing a modified example of the resonance circuit unit of the voltage controlled oscillator according to the present embodiment.

47A and 47B are diagrams for explaining another modification of the resonant circuit section of the voltage controlled oscillator according to the present embodiment.

48 (a) and 48 (b) are diagrams for explaining another modification of the resonant circuit section of the voltage controlled oscillator according to the present embodiment.

FIG. 49 is a diagram showing a modification of the oscillation circuit unit of the voltage controlled oscillator according to the present embodiment.

50A and 50B are schematic diagrams showing an example of a case where the resonant circuit section of the voltage controlled oscillator according to the present embodiment is formed on a substrate.

51A to 51C are schematic views showing another example of the case where the resonant circuit section of the voltage controlled oscillator according to the present embodiment is formed on a substrate.

FIG. 52 is a block diagram showing a configuration of a conventional general mobile phone.

FIG. 53 is a diagram showing a configuration of a bias circuit generally used for an amplifier in a conventional mobile phone.

FIG. 54 is a diagram showing an example of a simulation result of a conventional bias circuit.

FIG. 55 is a diagram showing an example of a simulation result of a conventional bias circuit.

FIG. 56 is a diagram showing an example of simulation results of a conventional bias circuit.

FIG. 57 is a diagram showing an example of a simulation result of a conventional bias circuit.

FIG. 58 is a diagram showing an example of a simulation result of a conventional bias circuit.

FIG. 59 is a diagram showing an example of a simulation result of a conventional bias circuit.

FIG. 60 is a diagram showing an example of a simulation result of a conventional bias circuit.

FIG. 61 is a diagram showing an example of a simulation result of a conventional bias circuit.

FIG. 62 is a diagram showing a configuration of a general directional coupler used in a conventional mobile phone.

63A and 63B are diagrams showing a configuration of a general high-frequency filter circuit used in a conventional mobile phone, respectively.

FIG. 64 is a diagram showing a configuration of a general voltage controlled oscillator used in a conventional mobile phone.

FIG. 65 is a diagram showing an example of a conventional high frequency filter circuit compatible with dual bands.

FIG. 66 is a diagram showing an example of a conventional voltage controlled oscillator for dual band.

FIG. 67 is a diagram showing an example of a conventional dual-band compatible voltage controlled oscillator.

[Explanation of symbols]

1 Transmission System 2 Variable Attenuator (VATT) 3 Direct Modulator (MOD) 4 High Output Amplifier (HPA) 5 Hybrid (HYB: Directional Coupler) 6 Bandpass Filter (BPF) 7 Detection Circuit 8 Comparison Circuit 9 Reception System 10 band pass filter (BPF) 11 low noise amplifier (LNA) 12 reception down converter (MIX) 13 antenna 14 duplexer 15 local oscillator for RF band (voltage controlled oscillator) 16 to 27, 32 to 34, 66, 68 transmission Line (microstrip line) 28 Demultiplexing circuit 29,30 Matching circuit 31 Multiplexing circuit 32 Transmission line 35,46,67,77,88 Switch 40 Signal line 41,41A, 41B, 42 Dielectric resonator 43,44, 48, 51, 52, 63, 79, 82, 8
3, 87, L1 to L7 coils 49, 53, R3 to R9 resistors 45, 46, 64, 64A, 64B, D1 to D7 variable capacitance diodes (varactor diodes) 47, 50, 84 to 86 pin diodes 61 resonant circuit section 62 Oscillation circuit section 65, 69 to 76, 81, C2 to C26, C31 to C3
7, C5 ', C6' Capacitor 78, TR1 to TR9 Transistor (FET) 80 Resonance circuit 91 Substrate 92 Ground (GND) surface 93 RF line (signal line) 94 Adjustment open stub 95A, 95B Through hole 96 Strip line resonator 97 Adjustment groove

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H03F 3/60 H03F 3/60 H03G 3/30 H03G 3/30 B H03H 7/075 H03H 7/075 A H04B 1/18 H04B 1/18 C (72) Inventor Shinichi Kawai 2-1-1 Kitaichijo Nishi, Chuo-ku, Sapporo-shi, Hokkaido Fujitsu Hokkaido Digital Technology Co., Ltd. (72) Inventor Manabu Murakami Chuo-ku, Sapporo, Hokkaido Kita-Ichijo Nishi 2-chome, Fujitsu Hokkaido Digital Technology Co., Ltd. (72) Inventor Akio Sasaki Kita-Ichijo Nishi 2-chome, Chuo-ku, Sapporo, Hokkaido Fujitsu Hokkaido Digital Technology Co., Ltd.

Claims (3)

[Claims] 1. A high-frequency circuit, wherein some components are shared for all frequencies so as to correspond to a plurality of frequencies, and other components are connected to the some components depending on the frequency used. Alternatively, a high-frequency circuit characterized by being configured to be separated. 2. A high-frequency circuit, wherein some components are shared for all frequencies so as to support a plurality of frequencies, and other components can change their impedances according to the frequencies used. A high-frequency circuit, characterized in that 3. A high-frequency circuit, comprising a plurality of matching circuits for coping with a plurality of frequencies, each of which is connected through a demultiplexing / combining circuit. High frequency circuit.