JPH09275319A - 3-multiple frequency circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the 3-multiple frequency circuit with a small conversion loss by improving input output impedance characteristics and reducing leakage of an input signal to an output terminal. SOLUTION: An input terminal connects to an anti-parallel connection diode 4, an open stub 3 with a length of 1/4 wavelength with respect to a 3-multiple frequency of a basic frequency, and a short stub 2 with a length of 1/2 wavelength with respect to a 3-multiple frequency of the basic frequency. Furthermore, an output of the anti-parallel connection diode 4 connects to a short stub 6 with a length of 1/4 wavelength with respect to a 3-multiple frequency of the basic frequency, and a rejection filter 5 for the basic frequency being a series connection circuit consisting of a capacitor 8 and an inductance 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frequency tripler used in a microwave or millimeter wave band, and more particularly to an anti-parallel diode (hereinafter referred to as APD).
The present invention relates to a frequency tripler circuit using.

[0002]

2. Description of the Related Art A block diagram of a conventional frequency tripler using an APD is shown in FIG. 1 is the input terminal of the fundamental wave,
Reference numeral 3 is an open stub having a quarter wavelength at the triple frequency, 6 is a short stub having a quarter wavelength at the triple frequency, 4 is an APD, and 7 is an output terminal for the triple frequency.

Next, the operation will be described. If the currents flowing through the diode are i ₁ and i ₂ , respectively,

[0004]

[Equation 1]

[0005] In this case, i _s, the diode saturation current,
α is q / kT, k is Boltzmann's constant, T is absolute temperature, q
Represents the charge amount of electrons, and V represents a basic high frequency voltage.

Therefore, the combined current i of both diodes is
Becomes as follows.

[0007]

[Equation 2]

When the equation (3) is approximated,

[0009]

(Equation 3)

As described above, when the high frequency voltage of the fundamental wave is applied to the APD 4, the high frequency components output by the non-linear characteristic are only the odd harmonic components of the fundamental wave.

At this time, the tripled signal generated by the APD 4 is
Since the impedance of the open stub 3 becomes 0 at the triple frequency, it is totally reflected and is not output to the output terminal 7. On the output terminal side, the impedance of the short stub 6 becomes infinite at the triple frequency, so that the short stub 6 is not reflected and output.

The input signal has an impedance of the open stub 3 which is not infinite at the fundamental frequency.
A reflected wave is generated and only a part of the input signal is input to the APD 4. Further, since the impedance of the short stub 6 does not become 0 with respect to the fundamental frequency, the input signal leaks to the output terminal 7.

FIG. 5 shows another prior art, Japanese Patent Laid-Open No. 5-2.
It is the figure which showed the block diagram of the microwave circuit described in 51939 gazette. In the figure, 20 is an input terminal, 21
a and 21b are wires, 22 is an output terminal, 23 is a bias circuit, 24 to 27 are diodes, 30 is a first conductor,
31 is a second conductor, 32 is a coplanar quarter-wave balun, 33 and 42 are coplanar lines, 40 is a first ground conductor, 41 is a second ground conductor, and 42 is a signal line.

FIG. 6 is a principle diagram for explaining the circuit of FIG. 5, in which 50 is a coplanar quarter-wave balun 3.
2 is a transformer, and 51 is a transformer corresponding to the coplanar line 42 and the bias circuit 23.

Next, the operation will be described with reference to FIG. The signal input to the input terminal 20 enters the balanced mode by the transformer 50 and excites the diodes 24 to 27. If the input signal is represented by the voltage Ve ^ (jωt), the diode 2
The current generated at 4 is as in the following equation.

[0016]

(Equation 4)

Here, n is the order of the harmonic, and i _n is the current amplitude of the n-th harmonic. Since the current component is only the odd harmonic component, the odd harmonic component of the input signal is output to the output terminal 22.

In the microwave circuit described above, the input waves reflected by the diodes 24 to 27 become in phase at the input terminal 20 and are combined and output. Further, the output impedance at the tripled frequency also has a problem that a tripled signal output from the output terminal produces a reflected wave and cannot be matched.

[0019]

As described above,
The conventional technique has the following problems.

The first problem is that the input signal produces a reflected wave at the open stub 3 and only a part of the input signal is input to the APD 4, which deteriorates the conversion loss.

The reason is that the open stub 3 becomes a blocking filter having an impedance of 0 at the triple frequency, but does not become a pass filter having an infinite impedance at the input fundamental frequency.

The second problem is that the input signal leaks to the output terminal 7 side.

The reason is that the short stub 6 serves as a pass filter having an infinite impedance at the triple frequency, but does not serve as a blocking filter having an impedance of 0 at the input frequency.

The present invention has been made to solve the above problems, and improves the input / output impedance.
It is an object of the present invention to provide a frequency tripler in which the input signal leaks to the output terminal is small and the conversion loss is small.

[0025]

According to the present invention, in a frequency tripler circuit in which a tripled frequency of a fundamental frequency of an input signal is used as an output signal, an antiparallel diode is added to the input signal and a quarter of the tripled frequency. A wavelength open stub and a ½ wavelength short stub of the triple frequency are connected, and an output terminal of the anti-parallel diode has a ¼ wavelength short stub of the triple frequency and a rejection of the fundamental frequency. It is characterized by connecting with a filter.

In addition to the input terminal of the conventional frequency tripler,
The above object is achieved by inserting a short stub having a half wavelength of the tripled frequency and a rejection filter having a fundamental frequency into the output terminal.

According to the frequency tripler of the present invention having the above structure, the input impedance at the fundamental frequency is improved, so that the input signal can be efficiently input to the APD and the conversion loss can be reduced. Further, since the output impedance at the fundamental frequency is improved, the leakage of the input signal to the output terminal can be reduced.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an equivalent circuit of the frequency tripler of the present invention. Reference numeral 1 is an input terminal of a fundamental wave, 2 is a short stub having a half wavelength of a tripled frequency, 3 is an open stub having a quarter wavelength of a tripled frequency, 4 is an APD, 5 is a capacitor 8 and an inductance 9 are connected in series. A rejection filter having a connected fundamental frequency, 6 is a short stub having a quarter wavelength of a tripled frequency, and 7 is an output terminal.

Next, the operation of FIG. 1 will be described.

The input terminal 1 is open to the fundamental frequency and shorted to the tripled frequency by the short stub 2 and the open stub 3. Output terminal 7
Is made short-circuited with respect to the fundamental frequency by the ridismaction filter 5, and is opened with respect to the tripled frequency by the short stub 6. Therefore, the fundamental wave input from the input terminal 1 is input to the APD 4 without being reflected, and is reflected at the output terminal 7 so that it is not output. At this time, the third harmonic generated in the APD 4 is totally reflected at the input terminal 2 and is not output, and is output from the output terminal 7 without being reflected.

[0032]

Next, embodiments of the present invention will be described in detail.

FIG. 2 shows an open stub 3 formed on a thin film dielectric substrate 10 (alumina substrate, thickness: 0.254 mm) by a 50Ω microstrip line (gold, 5 μm).
The short stub 2 and the input / output signal lines 11 and 12 are formed. The rejection filter 5 is formed of an inductor 9 and a microchip capacitor 8 by Au wire bonding.

In order to make the resonance frequency of the rejection filter 5 coincide with the fundamental frequency, the capacitance of the capacitor 8 and Au
It suffices to adjust the wire bonding length. The fundamental wave input from the input terminal 1 through the signal line 11 is input to the APD 4 without being reflected, and the third harmonic generated in the APD 4 is reflected, so that the conversion loss is reduced. Further, the output terminal 7 does not reflect the third harmonic wave but suppresses the fundamental wave, so that leakage of the fundamental wave can be suppressed.

FIG. 3 shows the characteristics of this effect when the frequency tripler has a fundamental frequency of 2.17 GHz and the triple frequency 6.51 GHz is obtained in the configuration of FIG.

This figure shows a simulation result in which the output levels of the fundamental wave and the third harmonic are calculated with respect to the fundamental wave input level using the harmonic balance method.

In this figure, in order to make a characteristic comparison with the configuration of FIG. 4 described above, the respective characteristics are shown for both cases.

First, regarding the conversion loss, when the input level of the fundamental wave is +10 dBm, the level of the third harmonic wave is about -4.0 dBm in the present invention, and is therefore 14 dB. On the other hand, in the conventional technique, the level of the third harmonic is about −5.
It is 5 dBm, which is 15.5 dB. Therefore,
A conversion loss improvement of 1.5 dB is obtained.

Regarding the leakage of the fundamental wave, the output level of the present invention is suppressed to -44 dBm under the same conditions. On the other hand, in the conventional technique, 0 dBm is also output.

Therefore, the present invention improves the fundamental wave leakage of 44 dB.

[0041]

The first effect is that the leakage of the fundamental wave can be suppressed without reflecting the third harmonic wave output at the output terminal.

The reason is that the suppression of the fundamental wave at the output terminal is performed by the rejection filter instead of the open stub having a quarter wavelength of the fundamental frequency.

The second effect is that the fundamental wave is not reflected at the input terminal and is input to the APD, and the third harmonic generated at the APD is reflected at the input terminal. This can reduce the conversion loss.

The reason is that the input terminal is open at the basic frequency and short-circuited at the triple frequency by the mutual stub of the half wavelength short stub and the quarter wavelength open stub of the triple frequency. Is.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of an embodiment of the present invention.

3 is an input / output characteristic in the configuration of FIG.

FIG. 4 is a block diagram showing a conventional technique.

FIG. 5 is a configuration diagram showing another conventional technique.

6 is an equivalent circuit of the configuration of FIG.

[Explanation of symbols]

1 Input terminal 2 Short stub of 1/4 wavelength for 3 multiplied frequency 3 Open stub for 1/4 wavelength of 3 multiplied frequency 4 Anti-parallel diode (APD) 5 Rejection filter of fundamental frequency 6 1/4 wavelength for 3 multiplied frequency Open stub 7 Output terminal 8 Inductance 9 Capacitor 10 Dielectric board

Claims (4)

[Claims] 1. A frequency tripler circuit which outputs a tripled frequency of a fundamental frequency of an input signal as an output signal, wherein the input signal includes an anti-parallel diode, an open stub having a quarter wavelength of the tripled frequency, and 1 of multiplied frequency
1/2 wavelength short stub is connected, and the output terminal of the anti-parallel diode is ¼ of the triple frequency.
A frequency tripler circuit in which a short stub of wavelength and a rejection filter of the fundamental frequency are connected. 2. The rejection filter comprises a series connection circuit of a capacitor and an inductance, one end of which is connected to the ground and the other end of which is connected to the anti-parallel diode, and a series resonance frequency is set to the fundamental frequency. The frequency tripler circuit according to claim 1. 3. The frequency tripler according to claim 1, wherein the input signal is a high frequency signal in a microwave band or a millimeter wave band. 4. The frequency tripler circuit comprises, on a dielectric substrate, the anti-parallel diode, an open stub having a quarter wavelength of the tripled frequency using a microstrip line, and a tripled frequency of 1. 2. A short wavelength stub having a / 2 wavelength and a short wavelength stub having a quarter wavelength of the tripled frequency are mounted, and the rejection filter is formed by wire bonding and a microchip controller. Frequency tripler.