JPS62111A - Microwave power amplifier - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] A main strip line that resonates at the signal frequency and connected to the output end of an amplification element that performs on/off operations at the signal frequency is short-circuited and connected to different even-order harmonics. An arbitrary number of resonant elements are coupled to the main strip line at the positions where they are short-circuited at that frequency when viewed from the output end of the amplification element, and each of the arbitrary number of resonant elements which are short-circuited for different odd harmonics is amplified. By coupling each element to the main strip line at a position that is open at that frequency when viewed from the output end of the element, class F mode operation is performed.
Improve the efficiency of power amplifiers.

[Industrial application field]

The present invention relates to a microwave power amplifier, and more particularly to a microwave power amplifier whose efficiency is improved by performing class F mode operation.

Almost all of the power required to drive a microwave transmission circuit is consumed by a power amplifier. Therefore, for example, in a portable communication device, the efficiency of the power amplifier is a factor that determines the size of the drive power source, the size of the heat sink, etc. Therefore, it is desired to improve the efficiency of power amplifiers, which directly leads to improving the performance of communication devices and reducing weight and dimensions.

On the other hand, class F mode operating power amplifiers have the advantage of extremely high efficiency, but conventionally known configurations are not necessarily suitable for microwave applications.

The present invention provides an improved class F mode operating microwave power amplifier suitable for microwave applications.

[Conventional technology]

FIG. 5 shows the configuration of a conventional power amplifier operating in class F mode. In the figure, reference numeral 1 denotes an FET, whose drain D is supplied with a power supply +vp via a high-frequency choke 2, whose gate G is given high-frequency excitation, and whose source S is grounded. The high frequency output at the drain D of FET l is applied to the tank circuit (L, C) 5 via the coupling capacitor 3 and the λ/4 (λ is the signal frequency) coaxial line 4 to produce a signal output, and the load resistance (RL) Consumed at 6.

FIG. 6 shows signal waveforms at various parts in the power amplifier shown in FIG. 5, where (a) is the voltage waveform at the drain D, (bl is the voltage waveform at the load 6, and (C) is the current waveform at the drain D, and +d) is the current waveform at the load resistor 6.

In FIG. 5, the impedance of the tank circuit 5 is infinite with respect to the signal frequency. The coaxial line 4 is equivalent to a half-wavelength line for even-order harmonics, and is equivalent to a quarter-wavelength line for odd-order harmonics, so the FET
The drain of 1 is short-circuited to the ground for even-order harmonics, and is open for odd-order harmonics. FET 1 is excited so that it is on for half the signal period and off for the remaining half period. Therefore Fil! The drain voltage of 71 is zero when it is on, but only odd harmonics appear when it is off, so it becomes a rectangular waveform as shown in FIG. 6 (al), and its amplitude is 2V.

Only the fundamental frequency component of this drain voltage appears in the load 6, but its phase is delayed by 90° due to the λ/4 coaxial line 4 (FIG. 6(b)). Further, the current in the load 6 is in phase with this (FIG. 6(d)).

On the other hand, when FET 1 is off, the drain current is zero, but when it is on, the coaxial line 4 is open to odd harmonics, so the drain current consists of only the fundamental wave and even harmonics, and therefore the drain current is zero. The current forms a half-wave rectified waveform as shown in FIG.

Like this PI! When T1 is off, no current flows due to the odd harmonic voltage appearing at the drain D, so no power consumption occurs. Furthermore, when FET 1 is on, even-order harmonic current flows through the drain D of the tank circuit 5. It circulates through the coaxial line 4, but since the voltage drop therebetween is zero, no power consumption occurs either.Therefore, the DC input at the drain of FET 1 is all consumed as a fundamental frequency signal in the load 6, and its efficiency is Ideally it is 100%. Actually Fl! Creates a distortion in the drain current based on the saturation resistance (Ron) 7 of T1,
Efficiency will not be 100%. Regarding such a power amplifier operating in class F mode, please refer to Frederic H. Larger, "Using PET as a power amplifier to increase transmitter efficiency" Nikkei Electronics L976.9.20 p.
It is described in detail in 117-126 etc.

[Problem that the invention seeks to solve]

In a power amplifier operating in class F mode, by connecting an impedance element to the output terminal of the amplification element that is short-circuited for even-order harmonic components of the output and open for odd-order harmonic components, Achieves high efficiency,
In the prior art shown in FIG. 5, a λ/4 coaxial line and a parallel resonant circuit are used to realize such impedance.

However, the above-mentioned impedance element is not necessarily suitable for a class F mode operating power amplifier for microwaves due to its size and other reasons. Furthermore, due to the influence of the output capacitance, output inductance, etc. of the microwave element, there is a problem in that a simple circuit as described above deviates from the ideal class F mode operating conditions.

[Means for solving problems]

FIG. 1 shows the basic configuration of the present invention.

Reference numeral 101 denotes an amplifying element, which is connected between the DC power source (b) and ground, and performs on/off operations controlled by the input signal frequency.

102 is a main strip line, for example, λ/4 (λ
is connected to the output terminal of the amplification element and resonates with the signal frequency.

Reference numeral 103 denotes an arbitrary number of resonant elements, each of which performs co-imaging for different even-order harmonics, and is coupled to the main strip line at the output end of the amplification element at a position where a short circuit occurs at each resonant frequency.

Reference numeral 104 denotes an arbitrary number of resonant elements, each resonating with a different odd-numbered harmonic, and coupled to the main strip line at the output end of the amplifying element at a position that is open at each resonant frequency.

[For production]

Each resonant element coupled to the main strip line that resonates at the signal frequency connected to the output end of the amplification element provides a short circuit for even harmonics of the output and an open circuit for odd harmonics. Therefore, class F mode operation of the power amplifier, which operates on and off at the signal frequency, is realized, and high efficiency of the power amplifier is achieved.

〔Example〕

FIG. 2 is a diagram showing an embodiment of the present invention, and 11 is a P
I! T, 12 is an input side matching circuit, 13 is an input terminal,
14 is the gate power supply, 15 is approximately λ/ with respect to the fundamental frequency.
4 main strip lines, 16-1 to 16-n, 17-
1 to 17-n are LC series resonant circuits, 18 is an output side matching circuit, 19 is an output terminal, and 20 is a drain power supply.

In FIG. 2, PE711 has its gate G given excitation at frequency f from input terminal 13 via input side matching circuit 12, and the fundamental wave output at its drain D is resonated by main strip line 15, and the output side matching circuit A signal output is taken out to an output terminal 19 via 18. FET
11 has its source S grounded, and the gate power supply 1
4 to gate voltage -V (1 is given, drain power supply 2
A drain voltage vo is given from 0.

The LC series resonant circuits 16-1 to 16-n are connected to the main strip line 15 in a shunt manner, and the position thereof is FE71.
When viewed from the drain D of 1, the second harmonic f2
~ 2nd nth harmonic f 1 at each frequency at the position where there is a short circuit for 2n, i.e. at the output end or from
/2 wavelengths apart. Also LC
The series resonant circuits 17-1 to 17-n are, for example, LC series resonant circuits 16-1 to 16-n with respect to the main strip line 15.
It is connected to the main strip line 15 in a shunt manner on the side opposite to n, and its position is 3rd harmonic f3 to 20+1st harmonic f3 when viewed from the drain D of PE711.
The position is open to 2n+1, that is, the position is 1/4 wavelength apart from the output end at that frequency, or the position is an integer multiple of 1/2 wavelength at each frequency from the output end. LC series resonant circuit 16-1~
16-n and 17-1 to 17-n are each PET
Although they are generally arranged in order of higher order from the drain D of No. 11, they are not necessarily arranged in this order, and may be arranged at positions spaced apart from such a position by an integer multiple of 1/2 wavelength at that frequency.

As a result of this configuration, the impedance connected to the drain D of FET 11 is short-circuited for each even-order harmonic component of the output, and is open-circuited for each odd-order harmonic component. , class F mode operation is performed.

In this case, the constants of each LC series resonant circuit 16-1 to 16-n and 17-1 to 17-n and the main strip line 1
5 can be changed independently. Therefore, the resonant frequency and phase for each harmonic can be adjusted independently, so FET 1
Even if there are variations in the output capacitance Co and output inductance Lo of 1, it can be adjusted so that each harmonic is completely short-circuited or open, so that F
The original operation of class mode can be realized in the microwave band.

[Second Embodiment] FIG. 3 shows another embodiment of the present invention,
The same parts as in Fig. 2 are indicated by the same numbers, and 21-1
21-n and 22-1 to 22-n are λ/2 strip line resonators.

The λ/2 strip line resonators 21-1 to 21-n are L-shaped, and each has a second harmonic f2 to a second harmonic of the signal frequency.
It has a length that is short-circuited for the first harmonic f2n, and is laterally coupled to the main strip line 15 by its - side, and its position is the second harmonic when viewed from the drain D of the PET 11. Wave f2 ~ 2nd n-th high opening wave r2
It is in a position where it is short-circuited with respect to n.

Further, the λ/2 strip line resonators 22-1 to 22-n have a similar shape, and each has a third harmonic f of the signal frequency.
It has a length that is short-circuited to the 3rd to 2nd n÷1 harmonics f2n+1, and is located on the opposite side of the main strip line 15 from the λ/2 strip line resonators 21-1 to 21-n, for example. , is laterally coupled to the main strip line 15 by its - side, and its position is at the drain D of the FET 11.
When viewed from above, the positions are open to the third harmonic f3 to the second n+1 harmonic f2n+1, respectively.

The positions of the λ/2 strip line resonators 21-1 to 21-n and 22-1 to 22-n on the main strip line 15 where such short circuits and opens occur are determined according to the embodiment shown in FIG. The same is true for .

As a result of this configuration, the impedance connected to the drain D of FET 11 is short-circuited for each even-order harmonic component of the output, and is open-circuited for each odd-order harmonic component. , class F mode operation is performed.

In this case, each λ/2 strip line resonator 21-1 to 21-2
The constants 1-n and 22-1 to 22-n and the connection positions to the main strip line 15 can be changed independently. The constants are changed, for example, by adjusting the length of the leg portions of the resonator or by changing the line width. Therefore, since the resonant frequency and phase for each harmonic can be changed independently, the FET
Even if there are variations in the output capacitance Co and output inductance Lo of 11, it can be adjusted to completely short-circuit or open for each harmonic. Therefore, the original operation of class F mode can be maintained in the microwave band. It can be realized.

[Third Embodiment] FIG. 4 shows the configuration of still another embodiment of the present invention. In the same figure, the same parts as in FIG. 2 are indicated by the same numbers, 23-1 to 23-n, 24-1' to 2.
4-n is a λ/2 strip line resonator. λ/2 strip line resonators 23-1 to 23-n and 24-1
~24-n is U-shaped, and has a length that causes a short circuit to the second high open wave f2 to the second niAi harmonic f2n and the third high open wave f3 to the 21st ÷ 1 harmonic f2n+1 of the signal frequency, respectively. and is coupled to the main stripline resonator 15 at its bottom portion, and its position is FIl'
When viewed from the drain D of T11, the second harmonic f2 to the second nth harmonic f2n are short-circuited, and the third
The position is open to harmonics f3 to 2n+1th harmonics f2n+1.

As a result of this configuration, the impedance connected to the drain D of FET 11 is short-circuited for each even-order harmonic component of the output, and is open-circuited for each odd-order harmonic component. Thus, F-stripe mode operation is performed.

In this case, each λ/2 strip line resonator 23-1 to 2
The constants of 3-n and 24-1 to 24-n and the connection positions to the main strip line 15 can be changed independently. The constants are changed, for example, by adjusting the length of both legs of the resonator or by changing the line width. Therefore, since the resonant frequency and phase for each harmonic can be changed independently, PE711
Even if there are variations in the output capacitance 1ico + output inductance Lo, it can be adjusted to completely short-circuit or open for each harmonic, thus realizing the original class F mode operation in the microwave band. can do.

The embodiment shown in FIG. 4 has an advantage over the embodiment shown in FIG. 3 in that the constants can be changed on both legs, making adjustment easier.

〔Effect of the invention〕

As explained above, according to the microwave power amplifier of the present invention, each resonant element coupled to the main strip line that resonates at the signal frequency is connected to the output end of the amplification element that performs on/off operation at the signal frequency. Since the output is short-circuited for even-order harmonics and open for odd-order harmonics, F-stripe mode operation can be performed, and high efficiency of the power amplifier is achieved. Ru.

According to the present invention, it is possible to miniaturize the device and it is suitable for microwave use, and it is also easy to adjust, so that the influence of the output capacitance of the microwave element, the output lead inductance, etc. can be removed, and the F-fringe can be correctly Mode operation can be performed.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the basic configuration of the present invention, Fig. 2 is a diagram showing one embodiment of the present invention, Fig. 3 is a diagram showing the configuration of another embodiment of the invention, and Fig. 4 is a diagram showing the main structure of the present invention. FIG. 5 is a diagram showing the configuration of a conventional F-stripe mode operating power amplifier; FIG. 6 is a diagram showing signal waveforms of various parts in the power amplifier of FIG. 5. That's 11-FET. 12 - input end matching circuit, +3 - input terminal, 14 - gate power supply, 15 - main strip line, 16-1 to 16-n, 17-1 to 17-n - L C series resonant circuit, 18 - output side Matching circuit, 19-output terminal, 20-drain power supply

Claims (3)

[Claims] (1) Power that has an amplification element (101) connected between a DC power source and ground that performs on/off operation at a signal frequency, and a main strip line (102) connected to the output end of the amplification element that resonates at the signal frequency. In the amplifier, an arbitrary number of resonant elements (103) are provided that are short-circuited to different even-order harmonics of the signal frequency, and the resonant elements (103) are provided at positions that are short-circuited to the respective resonant frequencies at the output end of the amplification element. An arbitrary number of resonant elements (104) are coupled to the main strip line and short-circuited to different odd-order harmonics of the signal frequency, and an open circuit is provided at the output end of the amplification element to each resonant frequency. A microwave power amplifier characterized in that the microwave power amplifier is coupled to the main strip line at a position. (2) The microwave power amplifier according to claim 1, wherein each of the resonant elements comprises an LC series resonant circuit that resonates at a respective resonant frequency. (3) The microwave power amplifier according to claim 1, wherein each of the resonant elements comprises a λ/2 strip line resonator for each resonant frequency.