JP3317139B2 - High power amplifier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-power amplifier for amplifying a high-frequency pulse having a rectangular wave envelope with high efficiency and suppressing spurious components included in an output wave.

[0002]

2. Description of the Related Art Spurious waves generated in amplifying means of a transmission device such as a transmitter in a radar system may affect other communication means and the like, and it is important to suppress the spurious waves. . In a radar system, a high-efficiency class C biased common-base bipolar transistor amplifier is widely used for transmitting high-power high-frequency pulses. The class C base-grounded bipolar transistor amplifier 1 illustrated in FIG. 8 comprises an NPN transistor having an emitter electrode 2 as an input terminal, a collector electrode 3 as an output terminal, and a base electrode 4 connected to a reference voltage which is ground. Includes bipolar transistor 5. Further, it usually includes an input side matching circuit (not shown) and an output side matching circuit (not shown). In this configuration, the collector electrode is positively biased with respect to the emitter electrode. In this amplifier, the base-emitter junction is forward biased during the negative half cycle of the input signal, causing the transistor to conduct and conduct the collector current of the output signal. At this time, the bias current in the emitter-base direction flows through the bias return 8 to the ground. Next, during the positive half cycle of the input signal, the base-emitter junction is reverse biased, causing the transistor to become non-conductive. At this time, the energy stored in the collector circuit is consumed by the load, thereby performing an efficient operation. Here, a case where a high-frequency pulse is input to the bipolar transistor 5 will be considered. At this time, the emitter-base direction self-bias current flowing to ground through bias return 8 will store energy in the bias circuit for the duration of the pulse. At the end of the high-frequency pulse, the input signal is suddenly cut off, and the energy stored as the base current during this transition period is released at the base input terminal, so that spurious vibration or ringing occurs on the output side. This oscillation appears as a spurious component in the output spectrum. FIG. 9 shows a relationship between an input waveform 9 and an output waveform 10 indicated by an envelope of a high-frequency pulse to the class C base-grounded bipolar transistor amplifier 1. As shown in the output waveform 10 in FIG. 9, the frequency component serving as the spurious component is generated at the time of sending the high-frequency pulse waveform at the time of the falling edge of the pulse indicated by the envelope of the end of the high-frequency pulse. In order to improve the spurious characteristics of the class C base-grounded bipolar transistor amplifier 1 having the characteristic of high output and high efficiency, the falling edge of the pulse waveform of the input waveform 9 indicated by the envelope of the high frequency pulse is changed slowly. In order to avoid a sudden change in current, a method was adopted. FIG. 10 shows a configuration disclosed in Japanese Unexamined Patent Publication No. 5-249225, "Spurious Frequency Suppressor". In a multi-stage amplifier for amplifying a high-output rectangular wave, a spurious frequency suppressor 12 including a variable attenuator and a pre-trigger (PIN diode bias controller) is provided after a pre-driver 11 to reduce spurious, and a high-frequency pulse whose waveform has been shaped is supplied to a driver amplifier 13. Is input to the final-stage amplifier. In class C amplification, the pulse waveforms of the input wave and the output wave to the amplifier are different. Further, waveform distortion at the time of the falling edge of the pulse affects spurious. Considering the case where a high-frequency pulse having a pulse waveform having a slowly changing envelope whose waveform is shaped is input, a low-level input wave is not amplified after class C amplification, so that the waveform sharply rises and falls. Also has a steep waveform, but the generation of unnecessary spurious components can be kept low.

[0003]

However, if a smooth input wave whose waveform has been shaped is subjected to class C amplification and then to class C amplification to obtain a required high output, a pulse having a sharp falling waveform is generated in this amplifier. As a result, large levels of spurs are generated. Therefore, smoothing of the high-frequency pulse waveform needs to be performed by the excitation amplifier immediately before the final-stage class C amplifier. However, this amplification stage has a considerably high power level. Requires a PIN diode that can withstand large power and a controller that controls the applied bias current, which becomes a relatively high current, at a high speed, and the transmission device becomes expensive. Further, in a high-power radar transmitter, a large number of such transmitters are arranged in parallel to combine power, or a large number of transmitters are used for power combining in space as a phased array. Therefore, there has been a problem that the size of the entire apparatus is increased, and the bias control section for waveform shaping in the high power section is spurred to increase the size.

SUMMARY OF THE INVENTION An object of the present invention is to provide a high-output amplifier with a low spurious level, which can use a highly efficient class C bipolar transistor amplifier with a simple configuration, without requiring the control unit to handle large power, and with high efficiency. I do.

[0005]

According to a first aspect of the present invention, there is provided a high power amplifier for amplifying an input high frequency pulse to obtain a desired high output. A stage amplifier is a class C bipolar transistor amplifier operated with a class C bias, and a field effect transistor is used as an amplifying element before the above class C bipolar transistor amplifier to operate with good linearity with a class A or class AB bias. Class or AB class field effect transistor amplifiers connected in multiple stages, connected to a semiconductor amplifier that amplifies incident radio waves to a level required for excitation of the class C bipolar transistor amplifiers, and connected to multiple stages of the semiconductor amplifiers. Field-effect transistor connected to at least one of the class-A or class-AB field-effect transistor amplifiers. A bias voltage or current applied to the field effect transistor of the static amplifier temporally controlled,
The input high-frequency pulse is provided with a waveform shaping bias control circuit for shaping the waveform so as to have an envelope waveform in which rising and falling are gradually changed, and at least the falling is gradually changed to the class C bipolar transistor amplifier. The shape of the high-frequency pulse whose waveform has been shaped so as to have the envelope waveform is stored and input.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 shows a configuration diagram of Embodiment 1 of a high-output amplifier according to the present invention. In the figure, reference numeral 14 denotes an A operating in the A class or the AB class.
A class 15 or class AB semiconductor amplifier 15 is a class C bipolar transistor amplifier. In the example shown in FIG. 1, the class-A or class-AB semiconductor amplifier 14 is configured to be cascaded in multiple stages. Among them, one or more stages of amplifiers may include those obtained by parallel power combining. Class or AB class operation is required.

Next, the operation will be described with reference to FIG. Now, let us consider a case where an incident radio wave 16 of a high-frequency pulse having an envelope waveform as shown in FIG. 2 is input from the input terminal 6 of the high-power amplifier shown in FIG. According to the present invention, the rising and falling edges of this pulse waveform change gradually, and the narrow band of the main spectrum and especially the falling edge change gradually, thereby reducing the adverse effect of the hole accumulation effect and reducing the spurious response. It is intended to obtain characteristics. The incident radio wave 16 is linearly amplified by a multi-stage Class A or AB class semiconductor amplifier 14, and a radio wave having the same pulse waveform as the incident radio wave 16 is obtained as an output of the multi-stage Class A or AB class semiconductor amplifier 14. It becomes the input of the transistor amplifier 15. Since the waveform of the gradually changing incident radio wave 16 is stored and becomes the incident wave of the C-class bipolar transistor amplifier 15, the waveform of the radio wave amplified by the C-class bipolar transistor amplifier 15 is as shown in FIG. The output radio wave 17 has a low-level cut-off pulse waveform with a slightly steep rising edge, but has no ringing waveform or the like due to the hole accumulation effect at the falling portion.

As described above, according to the configuration of the first embodiment, when the input radio wave 16 of the high frequency pulse of the envelope waveform whose rising and falling edges are gradually changed is input from the input terminal 6, the class A or the The AB-class semiconductor amplifier 14 linearly amplifies the signal to a level sufficient to excite the final-stage C-class bipolar transistor amplifier 15 and outputs a radio wave having the same pulse waveform as the incident radio wave 16.
A low-spurious, high-output amplifier amplified by the class bipolar transistor amplifier 15 can be realized. That is, by inputting a high-frequency pulse having an appropriate envelope waveform in which the falling edge is gradually changed, as described above, without using an expensive and large-sized spurious frequency suppressor or the like, high efficiency and low efficiency are achieved. There is an effect that a low-cost high-output amplifier having spurious characteristics can be obtained. In addition, as shown in FIG. 2, when a high-frequency pulse having an envelope waveform whose rise and fall are gradually changed is input, the occupied bandwidth of the main spectrum is also reduced and the high output is narrowed. There is an effect that an amplifier can be obtained.

Embodiment 2 FIG. 3 shows a configuration diagram of Embodiment 2 of the high-output amplifier of the present invention. In the figure, reference numeral 18 denotes a class A or A operating in a class A or a class AB using a field effect transistor as an amplifying element.
A class B field effect transistor amplifier 15 is a final class C bipolar transistor amplifier. The operation of the second embodiment is the same as that of the first embodiment. In the second embodiment, since the field-effect transistor of the field-effect transistor amplifier 18 is a voltage control element, the carrier accumulation effect at the junction is smaller than that of the bipolar transistor, and the transistor is operated in class A or class AB. Characteristic can be obtained. In the example shown in FIG. 3, the class-A or class-AB field-effect transistor amplifier 18 is configured to be cascade-connected in multiple stages. Good, but it is necessary to perform class A or class AB operation.

Embodiment 3 FIG. 4 shows a configuration diagram of Embodiment 3 of the high-output amplifier of the present invention. In the drawing, reference numeral 19 denotes a class A or class AB bipolar transistor amplifier which operates in class A or class AB using a bipolar transistor as an amplifying element, and reference numeral 15 denotes a final-stage class C bipolar transistor amplifier. The operation of the third embodiment is the same as that of the first embodiment.
Here, the bipolar transistor of the class A or class AB bipolar transistor amplifier 19 is a current control element and thus has a carrier accumulation effect at the junction. However, when operated in class A or class AB, the level at which the rectified current flows is also class C. The frequency component at the output of the class-A or class-AB bipolar transistor amplifier 19 is low spurious. Further, the configuration can be made at a relatively low price as compared with the case where the field effect transistor is used as an amplifying element, and there is an effect of reducing the price of the entire transmitter and realizing low spurious characteristics. In the example shown in FIG. 4, the class-A or class-AB bipolar transistor amplifier 19 is shown in a cascade-connected configuration in multiple stages. To achieve higher output. Needless to say, these also need to perform class A or class AB operation.

Embodiment 4 FIG. 5 is a configuration diagram of a fourth embodiment of the high-output amplifier according to the present invention. In the drawing, reference numeral 20 denotes a power distribution / combiner, 21 denotes a power distribution / combiner 20 at input / output terminals, and a plurality of C-classes connected in parallel between the power distribution / combiners 20 at the input / output terminals. This is a parallel power combining type parallel power combining class C bipolar transistor amplifier configured to include the bipolar transistor amplifier 15. Here, the output power of the preceding class A or class AB semiconductor amplifier 14 is distributed by the power distributor / combiner 20 and amplified by the class C bipolar transistor amplifier 15, respectively, and then the power is combined again by the power distributor / combiner 20. Is what you do. In the fourth embodiment, there is an effect that a high-efficiency amplifier with high efficiency and high output and low spurious characteristics can be obtained.

Embodiment 5 FIG. 6 is a configuration diagram of Embodiment 5 of the high-output amplifier according to the present invention. In the figure, reference numeral 22 denotes a waveform shaping circuit provided at the input end, followed by a plurality of cascade-connected Class A or Class AB semiconductor amplifiers 14, and provided with a Class C bipolar transistor amplifier 15 at the last stage. is there. The low-level radio wave incident from the input terminal 6 is shaped into an appropriate high-frequency pulse waveform having an envelope having a gentle rising and falling shape, and is input to the class A or class AB semiconductor amplifier 14, where the C-class bipolar at the final stage is formed. It is linearly amplified to a power level sufficient to excite the transistor amplifier 15.

According to the configuration of the fifth embodiment, the waveform shaping circuit 22 is provided at the input end and is connected to the class A or class AB semiconductor amplifier 14, so that low-level incident radio waves can be appropriately gently risen and fallen. What is necessary is just to shape the waveform of a high-frequency pulse with a shape, and high-performance waveform shaping can be realized at a small size and at a low price compared to the waveform shaping of a high-level radio wave. Note that A
Since the waveform of the high-frequency pulse having the envelope of the appropriate gentle rising and falling shapes amplified by the class-A or class-AB semiconductor amplifier 14 is stored up to the input of the class C bipolar transistor amplifier 15 at the final stage, the class C The spurious component of the output wave amplified to a high output by the bipolar transistor amplifier 15 can be suppressed low. In addition, since the input high-frequency pulse is shaped by the waveform shaping circuit so as to have an envelope waveform in which rising and falling are gradually changed, a high-output amplifier in which the occupied bandwidth of the main spectrum is also narrowed. Can be obtained.

Embodiment 6 FIG. FIG. 7 shows a configuration diagram of Embodiment 6 of the high-output amplifier of the present invention. In the figure, reference numeral 23 denotes a waveform shaping bias control circuit which is connected to at least one of the class A or class AB semiconductor amplifiers 14 cascade-connected in a plurality of stages, and controls a bias voltage or a current applied to an amplifying semiconductor element in the amplifier. It controls the time, and shapes the amplified output of the high-frequency pulse input to the amplifier into an appropriate high-frequency pulse waveform with a gentle rising and falling envelope. Input terminal 6
The radio wave of the high-frequency pulse incident from the A is sequentially amplified by a plurality of cascade-connected Class-A or Class-AB semiconductor amplifiers 14, and at least one of the Class-A or Class-AB semiconductor amplifiers 14 has an appropriate gentle rise and rise. It is shaped into a high-frequency pulse waveform having a falling envelope, and is amplified to a power level sufficient to excite the final-stage class C bipolar transistor amplifier 15 while maintaining the waveform. The output is input to the class C bipolar transistor amplifier 15 at the final stage, and is amplified with high efficiency and high output.

According to the sixth embodiment, the applicable amplifier of the waveform shaping bias control circuit 23 may be one of a plurality of cascade-connected class A or class AB semiconductor amplifiers 14, and is handled by one amplifier. Since the power is at a low power level, the configuration of the waveform shaping bias control circuit 23 can be simpler, smaller, and lower in cost than the case where waveform shaping is performed at a higher power level. In addition, the high-frequency pulse input by the waveform shaping bias control circuit is
Since the waveform is shaped so as to have an envelope waveform in which the rising and falling are gradually changed, the spurious component of the radio wave output from the output terminal 7 can be suppressed low, and the occupied bandwidth of the main spectrum can be narrowed. . Accordingly, there is an effect that a small-sized, low-priced, low spurious characteristic, high-output amplifier having a narrower occupied bandwidth of the main spectrum can be obtained.

When the semiconductor element is a field effect transistor, the waveform shaping bias control circuit 23 adjusts the time change of the bias value applied to the semiconductor amplifying element in the applied amplifier. It is composed of a bias control circuit for controlling each applied voltage to the source electrode. On the other hand, when the semiconductor element is a bipolar transistor, the semiconductor device is constituted by a bias control circuit for controlling each bias current of the base, the emitter or the collector.

[0017]

According to the first aspect of the present invention, the amplifier applied to the waveform shaping bias control circuit may be at least one of a class A or class AB field effect transistor amplifier, and the power handled by one amplifier is a low power level. Therefore, the configuration of the waveform shaping bias control circuit is simpler, smaller, and less expensive than the case where waveform shaping is performed at a relatively high power level. There is an effect that a characteristic high output amplifier can be obtained. Furthermore, since the input high-frequency pulse is shaped by the waveform shaping bias control circuit so as to have an envelope waveform in which the rising and falling are gradually changed, the exclusive bandwidth of the main spectrum is also narrowed. There is an effect that an output amplifier can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a high-output amplifier according to a first embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the high-output amplifier according to the first embodiment of the present invention;

FIG. 3 is a configuration diagram of a high-output amplifier according to a second embodiment of the present invention;

FIG. 4 is a configuration diagram of a high-output amplifier according to a third embodiment of the present invention.

FIG. 5 is a configuration diagram of a high-output amplifier according to a fourth embodiment of the present invention.

FIG. 6 is a configuration diagram of a high-output amplifier according to a fifth embodiment of the present invention.

FIG. 7 is a configuration diagram of a high-output amplifier according to a sixth embodiment of the present invention.

FIG. 8 is a configuration diagram of a conventional class C base-grounded bipolar transistor amplifier.

FIG. 9 is an explanatory diagram showing a relationship between an input waveform and an output waveform indicated by an envelope of a high-frequency pulse in a conventional class C base-grounded bipolar transistor amplifier.

FIG. 10 is a configuration diagram of a high-output amplifier using a conventional spurious frequency suppressor.

[Explanation of symbols]

1 Class C base-grounded bipolar transistor amplifier, 2
Emitter electrode, 3 collector electrode, 4 base electrode,
5 Bipolar transistor, 6 input terminal, 7 output terminal, 8 bias return, 9 input waveform, 10 output waveform, 11 pre-driver, 12 spurious frequency suppressor, 13 driver amplifier, 14 class A or AB
Class semiconductor amplifier, 15 class C bipolar transistor amplifier, 16 incident radio wave, 17 output radio wave, 18 A class or AB class field effect transistor amplifier, 19 A class or AB class bipolar transistor amplifier, 20 power distribution / combiner, 21 parallel power Synthetic class C bipolar transistor amplifier, 22 waveform shaping circuit, 23 waveform shaping bias control circuit.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Okamura 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Electric Corporation (56) References JP-A-62-191717 (JP, A) JP-A-4 -79406 (JP, A) Special Table 6-500859 (JP, A) Practical application A microfilm of the contents of the specification and drawings attached to the application form of Japanese Patent Application No. 2-104612 (Japanese Utility Model Application No. 4-61928). (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) H03F 3/24 H03K 5/02

Claims (1)

(57) [Claims] 1. Amplifying an input high-frequency pulse to a desired level
In the high-power amplifier that obtains the high output of
Class C bipolar transistor operated with Class C bias
The above-mentioned class C bipolar transistor amplifier
In the previous stage, class A using a field effect transistor
Or class A or class A operated with class AB bias with good linearity
Is a multi-stage class AB field effect transistor amplifier
Composed of the above-mentioned class C bipolar transistor
Semiconductor amplifier that amplifies to the level required for amplifier excitation
To the class A class connected in multiple stages of the semiconductor amplifier.
Or at least one of class AB field effect transistor amplifiers.
Connected and connected field effect transistor amplifier
Bias voltage applied to the field effect transistor of
The current is controlled temporally, and the input high-frequency pulse
Envelope wave with gently changing rising and falling edges
Waveform shaping bias control circuit for shaping the waveform to have a shape
To the class C bipolar transistor amplifier.
The envelope waveform with a gently falling edge
Save the shape of the high-frequency pulse whose waveform has been shaped to have
A high-output amplifier characterized by being input.