JP6526360B2 - High frequency splitter and high frequency circuit using the same - Google Patents

Description

  The present invention relates to a high frequency demultiplexer for separating radio waves of a plurality of input frequencies and a high frequency circuit using the same.

  There is a configuration using a plurality of band pass filters as a conventional high frequency branching filter (see, for example, Patent Document 1). This high frequency demultiplexer has a configuration in which band pass filters having a second harmonic, a third harmonic, and a fourth harmonic as pass bands are connected in parallel. In this high frequency demultiplexer, when radio waves including harmonics are input to the high frequency splitter, frequencies corresponding to the pass frequency band of the band pass filter are output from different terminals.

JP-A-8-65050

  However, the conventional high frequency duplexer requires a plurality of filters, so the size becomes large, and the demand for miniaturization has not been satisfied.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a high frequency duplexer which can be miniaturized.

  The high frequency branching filter according to the present invention comprises first to fourth terminals, and when the first terminal is an input terminal, the second terminal is an isolation terminal, and the third terminal is an output terminal at 0 °, The fourth terminal has a 90 ° hybrid circuit in a relationship of being an output terminal of -90 °, and of the input radio waves, a radio wave delayed in phase by 90 ° with respect to the first frequency with respect to the first frequency. Are provided to the second terminal, and a phase shift circuit is provided to provide the second terminal with a radio wave whose phase is advanced by 90 ° with respect to the radio wave given to the first terminal with respect to the second frequency.

  A high frequency branching filter according to the present invention comprises a 90 ° hybrid circuit having first and second terminals into which radio waves of a first frequency and a second frequency are inputted, and the third to be input to the second terminal The radio wave of frequency 1 is delayed by 90 ° in phase from the radio wave of the first frequency input to the first terminal, and the radio wave of the second frequency input to the second terminal is input to the first terminal The phase is 90 ° ahead of the radio wave of the second frequency. Accordingly, radio waves of the first frequency and the second frequency can be separated without using a plurality of filters, and miniaturization can be achieved.

It is a block diagram of the high frequency branching filter of Embodiment 1 of this invention. It is a block diagram at the time of equipping the 4th terminal of the high frequency splitter of Embodiment 1 of this invention with an open stub. It is a block diagram at the time of making the 4th terminal of the high frequency splitter of Embodiment 1 of this invention open. It is a block diagram at the time of equipping the input terminal of the high frequency splitter of Embodiment 1 of this invention with a short stub. It is a block diagram at the time of equipping the input terminal of the high frequency branching filter of Embodiment 1 of this invention with a short stub and resistance. It is a block diagram which shows the high frequency circuit of Embodiment 2 of this invention. It is a block diagram which shows the high frequency circuit of Embodiment 3 of this invention. It is a block diagram which shows the high frequency circuit of Embodiment 4 of this invention.

Hereinafter, in order to explain the present invention in more detail, a mode for carrying out the present invention will be described according to the attached drawings.
Embodiment 1
FIG. 1 is a block diagram of the high frequency branching filter according to the present embodiment.
As shown in FIG. 1, the high frequency branching filter according to the present embodiment equally divides the high frequency power input from the input terminal 100 and the input terminal 100 and provides a phase difference, and The 90 ° hybrid circuit 2 is provided with the fourth terminals 21, 22, 23, 24. The phase shift circuit 3 equally divides the high frequency input to the input terminal 100 by the in-phase distributor 31 and provides one output to the first terminal 21 of the 90 ° hybrid circuit 2 and the other output as the fundamental wave. , And the second terminal 22 of the 90 ° hybrid circuit 2 via the transmission line 32 having a 1⁄4 wavelength. Here, when the first terminal 21 of the 90 ° hybrid circuit 2 is an input (IN) terminal, the second terminal 22 is an isolation (ISO) terminal, and the third terminal 23 is a 0 ° output terminal, the fourth Terminal 24 is in a relationship of becoming a -90.degree. Output terminal. The 90 ° hybrid circuit 2 is configured by, for example, a Lange coupler or the like.

Next, the operation of the high frequency demultiplexer of the first embodiment will be described.
The fundamental wave which is the first frequency and the third harmonic which is the second frequency, which are input from the input terminal 100, are respectively divided by the in-phase distributor 31 into two with equal amplitude in the phase shift circuit 3. One output of the in-phase distributor 31 is input to the first terminal 21 of the 90 ° hybrid circuit 2, and the other output of the in-phase distributor 31 is 90 ° via the transmission line 32 which has a quarter wave at the fundamental wave. The signal is input to the second terminal 22 of the hybrid circuit 2. At this time, the fundamental wave input to the second terminal 22 of the 90 ° hybrid circuit 2 is 90 ° out of phase with the fundamental wave input to the first terminal 21 and is input to the second terminal 22. The third harmonic is 90 ° ahead of the third harmonic input to the first terminal 21.

  The 90 ° hybrid circuit 2 shifts the high frequency input to the first terminal 21 by θ phase shift and outputs it from the third terminal 23, shifts the phase by θ-90 ° and outputs it from the fourth terminal 24. Similarly, the high frequency input to the second terminal 22 is phase shifted by θ and output from the fourth terminal 24, and the phase is shifted by θ-90 ° and output from the third terminal 23. Here, θ is set to 0 ° in order to simplify the description.

The fundamental wave input to the first terminal 21 of the 90 ° hybrid circuit 2 and the fundamental wave delayed by 90 ° input to the second terminal 22 become reverse phase synthesis at the third terminal 23 and are not output. The four terminals 24 are in-phase combined and output. On the other hand, the third harmonic wave input to the first terminal 21 and the third harmonic wave advanced by 90 ° input to the second terminal 22 become reverse phase synthesis at the fourth terminal 24 and are not output. The terminal 23 is in-phase combined and is output.
Therefore, the fundamental wave and the third harmonic wave input to the input terminal 100 are divided and output from the fourth terminal 24 and the third terminal 23, respectively.

  In the above description, the first frequency is the fundamental wave, and the second frequency is the third harmonic, but the phase shift circuit 3 similarly applies to the second terminal 22 of the 90 ° hybrid circuit 2 at other frequencies. The phase of the radio wave of the first frequency input is delayed by 90 ° with respect to the radio wave of the first frequency input to the first terminal 21, and the phase of the radio wave of the second frequency input to the second terminal 22 Can be demultiplexed by advancing the phase by 90 ° with respect to the radio wave of the second frequency input to the first terminal 21.

  Further, as shown in FIG. 2, by providing an open stub 40 of 1⁄4 wavelength by the fundamental wave at the fourth terminal 24 of the 90 ° hybrid circuit 2, the third harmonic wave divided at the third terminal 23 The fundamental wave can be reflected back to the input terminal 100 without affecting the Further, as shown in FIG. 3, even when the fourth terminal 24 of the 90 ° hybrid circuit 2 is opened, the fundamental wave is reflected to the input terminal 100 without affecting the third harmonic similarly divided. Can be returned. As described above, by reflecting the fundamental wave back to the input terminal 100, for example, when a high frequency splitter is applied as one of the feedback circuits of the oscillator, the loop gain can be improved and the output frequency can be increased. It has the effect of being able to

  Furthermore, as shown in FIG. 4, the input terminal 100 may be provided with a short stub 41 having a fundamental wave of 1⁄4 wavelength. Thereby, the second harmonic wave can be reflected without affecting the fundamental wave and the third harmonic wave, and the input of the second harmonic wave can be suppressed and separated. For example, when a high frequency duplexer is applied to an oscillator, the oscillator outputs a fundamental wave, a second harmonic and a third harmonic. Here, when it is desired to take out the fundamental wave and the third harmonic wave, since the output of the second harmonic wave is unnecessary, this can be suppressed as the input, and the radiation of the unnecessary wave can be suppressed.

  Further, as shown in FIG. 5, the input terminal 100 may be provided with a short stub 41 and a resistor 42 of 1⁄4 wavelength as a fundamental wave. The resistor 42 is connected to one end of the short stub 41 whose fundamental wave is open. As a result, the second harmonic can be attenuated without affecting the fundamental wave and the third harmonic, input of the second harmonic can be suppressed, and radiation of unnecessary waves can be suppressed.

  As described above, according to the high frequency branching filter of the first embodiment, when the first to fourth terminals are provided and the first terminal is an input terminal, the second terminal is an isolation terminal, The 90 ° hybrid circuit in which the 3rd terminal is a 0 ° output terminal and the 4th terminal is a −90 ° output terminal, and the radio wave to be applied to the first terminal with respect to the first frequency of the input radio waves A phase-shifting circuit which applies to the second terminal a radio wave delayed in phase by 90 ° to the second terminal and to the second terminal a radio wave advanced in phase by 90 ° with respect to the second frequency with respect to the second frequency; Thus, radio waves of the first frequency and the second frequency can be separated without using a plurality of filters, and miniaturization can be achieved.

  Further, according to the high frequency demultiplexer of the first embodiment, the first frequency is the fundamental wave, the second frequency is the third harmonic, and the phase shift circuit is configured to receive the first harmonic and the third harmonic. An in-phase distributor for distributing in-phase and equal-amplitude to the terminal and the second terminal, and provided between the in-phase distributor and the second terminal, according to the electrical length between the in-phase distributor and the first terminal Also, since a fundamental wave and a transmission line long by 1/4 wavelength are provided, it is possible to demultiplex and output a fundamental wave and a third harmonic wave.

  Further, according to the high frequency demultiplexer of the first embodiment, since the fourth terminal is provided with the open stub having the 1⁄4 wavelength at the first frequency, the split third harmonic is affected. Instead, the fundamental wave can be reflected back to the input terminal of the high frequency demultiplexer.

  Further, according to the high frequency branching filter of the first embodiment, since the short stub having the 1⁄4 wavelength at the first frequency is provided at the input terminal of the high frequency branching filter or the phase shift circuit, The second harmonic wave can be reflected without affecting the second harmonic wave, and the input of the second harmonic wave can be suppressed and separated.

  Further, according to the high frequency branching filter according to the first embodiment, since the resistor is provided at the tip of the short stub which is open at the first frequency, the second harmonic can be generated without affecting the fundamental wave and the third harmonic. It can be attenuated to suppress the double wave input.

Second Embodiment
FIG. 6 is a block diagram showing a high frequency amplifier using the high frequency splitter of the first embodiment as the high frequency circuit of the second embodiment.
In FIG. 6, the high frequency branching filter 1a is the high frequency branching filter shown in FIG. 4 of the first embodiment, and the corresponding parts are denoted by the same reference numerals and the description thereof will be omitted. The output of the amplifier 5 is provided to the input terminal 100 in the high frequency demultiplexer 1a, and the third terminal 23 of the 90 ° hybrid circuit 2 in the high frequency splitter 1a has a third harmonic and a quarter wavelength. An open stub 43 is provided.

Next, the operation of the second embodiment will be described.
The operation of the high frequency demultiplexer 1a is the same as that of the first embodiment. However, in the high frequency duplexer 1a shown in FIG. 6, the short stub 41 shorts the second harmonic wave and reflects it independently of the fundamental wave and the third harmonic wave, and the open stub 43 independently of the fundamental wave and the second harmonic wave. The third harmonic can be reflected back to the input terminal 100. Therefore, it is possible to independently design the phase of the second harmonic by the electrical length from the amplifier 5 to the short stub 41 and the phase of the third harmonic by the electrical length from the amplifier 5 to the open stub 43.

  As described above, in the high frequency circuit according to the second embodiment, since the phases of the fundamental wave, the second harmonic, and the third harmonic can be designed independently, harmonic processing becomes easy. That is, in the harmonic processing, the fundamental wave and harmonics such as the second harmonic and the third harmonic are combined to form a desired waveform. These phase relationships are then important. For example, when the fundamental wave and the third harmonic wave are combined in phase, it approaches a rectangle, but when designing the phase of the second harmonic wave, when the phases of the fundamental wave and the third harmonic wave change and deviate from the in-phase relationship, good synthesis can be performed The waveform collapses. Accordingly, the ability to design the phases of the fundamental wave and the harmonics independently facilitates harmonic processing or waveform formation.

  As described above, according to the high frequency circuit of the second embodiment, the amplifier is connected to the input terminal of the high frequency demultiplexer or the phase shift circuit of the first embodiment, and the third terminal has the second frequency. The provision of the open stub with a 1⁄4 wavelength facilitates harmonic processing and improves the power consumption of the amplifier.

Third Embodiment
FIG. 7 is a block diagram showing a high frequency oscillator using the high frequency branching filter of the first embodiment as the high frequency circuit of the third embodiment.
In FIG. 7, the high frequency branching filter 1 is the high frequency branching filter shown in FIG. 1, and the corresponding parts are denoted by the same reference numerals and the description thereof will be omitted. The drain terminal of the transistor 60 is connected to the input terminal 100 in the high frequency demultiplexer 1, and the fourth terminal 24 in the high frequency splitter 1 is open. The transistor 60 has a feedback circuit 61 and a feedback circuit 62 at its source terminal and gate terminal, respectively.

Next, the operation of the third embodiment will be described.
The operation of the high frequency demultiplexer 1 is the same as the operation of the configuration shown in FIG. 1 of the first embodiment. However, the high frequency demultiplexer 1 shown in FIG. 7 operates as one of the feedback circuits of the oscillator, the fundamental wave reflected at the fourth terminal 24 of the 90 ° hybrid circuit 2 returns to the input terminal 100, and the transistor It is input to 60. In the high frequency oscillator according to the third embodiment, the fundamental wave is serially fed back. The high frequency (noise at first) input to the gate terminal of the transistor 60 is amplified by the transistor 60 and output to the drain terminal, and the high frequency reflected by the drain terminal side circuit (here, the high frequency demultiplexer 1) is the transistor 60 The signal is input to the feedback circuit 61 via the drain and source of and reflected. Further, it is input to the feedback circuit 62 via the gate and the source of the transistor 60 to be reflected and is fed back to the gate terminal of the transistor 60 so as to be in phase. This high frequency is the oscillation frequency.

In order for the oscillator to perform the oscillating operation, the gain obtained by making a round trip between the transistor and the feedback circuit connected to each terminal of the transistor needs to be positive, and the larger the easier it is to perform the oscillating operation. The high frequency oscillator shown in FIG. 7 feeds back the fundamental wave that performs the oscillation operation to the transistor 60 without outputting the fundamental wave to the external load, so that the loop gain of the oscillator is improved and the oscillator easily performs the oscillation operation. Furthermore, the third harmonic obtained by the oscillation operation is output from the third terminal 23 of the 90 ° hybrid circuit 2.
Although an example in which the high frequency splitter is connected to the drain terminal as one of the feedback circuits is shown here, the high frequency splitter may be provided on the gate terminal or the source terminal.

  As described above, according to the high frequency circuit of the third embodiment, the input terminal of the high frequency demultiplexer of the first embodiment configured as a feedback circuit is connected to at least one of the terminals of the transistor, and oscillation occurs. Since the operation is performed, it is possible to feed back the fundamental wave to be oscillated by the high-frequency demultiplexer and to output the third harmonic which is the harmonic thereof, so that the oscillation operation can be easily realized. In addition, phase noise can be improved because transistors and resonators with high performance can be used rather than using an oscillator at a frequency corresponding to the third harmonic directly. This is because the lower the frequency, the lower the loss and the smaller the parasitic component.

  Further, according to the high frequency circuit of the third embodiment, since the fourth terminal is opened, the fundamental wave is not applied to the input terminal of the high frequency demultiplexer without affecting the third harmonics. It can be reflected back.

Fourth Embodiment
FIG. 8 is a block diagram showing a PLL synthesizer using the high frequency branching filter of the first embodiment as the high frequency circuit of the fourth embodiment.
In FIG. 8, the high frequency branching filter 1 is the high frequency branching filter shown in FIG. 1, and the corresponding parts are denoted by the same reference numerals and the description thereof will be omitted. A voltage controlled oscillator (VCO) 70 of a phase locked loop (PLL) is connected to the input terminal 100 of the high frequency demultiplexer 1, and the fundamental wave output from the fourth terminal 24 of the 90 ° hybrid circuit 2 is a PLL circuit unit The configuration is such that the output of the PLL circuit unit 71 is supplied to the voltage control oscillator 70 to perform negative feedback control. Here, the PLL circuit unit 71 is a circuit including a phase comparator, a reference oscillator, a loop filter, a prescaler, and the like, and the voltage control oscillator 70 and the PLL circuit unit 71 constitute a known phase synchronization circuit. .

Next, the operation of the fourth embodiment will be described.
The operation of the high frequency demultiplexer 1 is the same as that of the first embodiment. The voltage control oscillator 70 is a circuit whose oscillation frequency is changed by controlling a voltage, and performs oscillation operation with a fundamental wave. The fundamental wave output from the voltage control oscillator 70 is output from the fourth terminal 24 of the 90 ° hybrid circuit 2 via the high frequency demultiplexer 1. The fundamental wave output from the fourth terminal 24 is phase-compared with the reference frequency output from the reference oscillator in the PLL circuit unit 71, and the PLL circuit unit 71 supplies the voltage control oscillator 70 with a voltage according to the phase error. The voltage control oscillator 70 corrects the oscillation frequency according to the applied voltage. The third harmonic generated in this oscillation operation is not output from the fourth terminal 24 of the 90 ° hybrid circuit 2 but is output from the third terminal 23.

  As described above, according to the high frequency circuit of the fourth embodiment, the high frequency circuit of the fourth embodiment is provided with a phase synchronization circuit for inputting the output of the fourth terminal of the high frequency demultiplexer of the first embodiment as a radio wave for phase comparison with the reference frequency. Since the output of the voltage controlled oscillator of the phase locked loop is connected to the input terminal of the high frequency demultiplexer, the following effects can be obtained. That is, the high frequency wave splitter connected to the output of the oscillator demultiplexes the fundamental wave to be oscillated and its third harmonic, the fundamental wave as an input wave to the phase locked loop, and the third harmonic as an output wave to the outside By doing this, it is possible to reduce the number of prescalers used in the phase synchronization circuit or to reduce the number of divisions, thereby achieving the miniaturization of the PLL synthesizer and the improvement of the phase noise. Further, as in the third embodiment, since transistors and resonators with better performance can be used rather than directly configuring the oscillator at a frequency corresponding to the third harmonic, the effect of improving the phase noise of the oscillator can be obtained.

  In the scope of the invention, the present invention allows free combination of each embodiment, or modification of any component of each embodiment, or omission of any component in each embodiment. .

  As described above, the high-frequency demultiplexer and the high-frequency circuit according to the present invention relate to the configuration of a high-frequency splitter that splits radio waves of a plurality of input frequencies, and the configuration of a high-frequency circuit using this high-frequency splitter. , High frequency amplifier, high frequency oscillator, PLL synthesizer, etc.

  1, 1a High frequency splitter, 2 90 ° hybrid circuit, 3 phase shift circuit, 5 amplifier, 21 first terminal, 22 second terminal, 23 third terminal, 24 fourth terminal, 31 common mode distributor , 32 transmission lines, 40, 43 open stubs, 41 short stubs, 42 resistors, 60 transistors, 61, 62 feedback circuits, 70 voltage controlled oscillators, 71 PLL circuit units, 100 input terminals.

Claims (9)

When the first to fourth terminals are provided and the first terminal is an input terminal, the second terminal is an isolation terminal, the third terminal is an output terminal at 0 °, and the fourth terminal is- 90 ° hybrid circuit in the relationship of 90 ° output terminal,
Among the radio waves input, a radio wave delayed in phase by 90 ° from the radio wave given to the first terminal with respect to the first frequency is given to the second terminal, and the first terminal with respect to the second frequency And a phase shift circuit for applying to the second terminal a radio wave whose phase is advanced by 90 ° relative to a radio wave to be applied to the high frequency demultiplexer. The first frequency is a fundamental wave, and the second frequency is a third harmonic.
An in-phase distributor that distributes the fundamental wave and the third harmonic wave to the first terminal and the second terminal in phase and with equal amplitude;
The transmission line is provided between the in-phase distributor and the second terminal, and has a fundamental wave that is longer by 1/4 wavelength than the electrical length between the in-phase distributor and the first terminal. The high frequency branching filter according to claim 1, characterized in that   The high frequency branching filter according to claim 1, characterized in that the fourth terminal is provided with an open stub having a quarter wavelength at the first frequency.   The high frequency demultiplexer according to claim 1, further comprising a short stub having a quarter wavelength at the first frequency at an input terminal of the phase shift circuit.   5. The high frequency branching filter according to claim 4, further comprising a resistor at a tip of the short stub which is open at the first frequency.   An amplifier is connected to an input terminal of the phase shift circuit using the high frequency branching filter according to claim 4, and an open stub having a 1/4 wavelength at the second frequency is provided at the third terminal. Characteristic high frequency circuit.   2. The high frequency circuit according to claim 1, wherein the input terminal of the high frequency duplexer according to claim 1 is connected to at least one of the terminals of the transistor as a feedback circuit to perform an oscillation operation.   The high frequency circuit according to claim 7, wherein the fourth terminal is open.   A high-frequency splitter according to claim 1, and a phase synchronization circuit for inputting as a radio wave for phase comparison of the output of the fourth terminal of the high-frequency splitter with a radio wave of a reference frequency, A high frequency circuit characterized in that an output of a voltage controlled oscillator is connected to an input terminal of the high frequency splitter.

Images