JPS6259490B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in semiconductor amplifiers for microwave and millimeter waves that obtain large power by operating a plurality of semiconductor amplifiers in parallel.

FIG. 1 shows an example of a conventional device of this type. 1 in the diagram
is a power divider, and 2 is a semiconductor unit amplifier.
As the distributor 1 for microwave and millimeter wave bands, there is a magic T composed of a waveguide, a branch line coupler, etc., and as the unit amplifier 2,
FET constructed using microstrip lines
(Field Effect Transistor) amplifiers are well known.

The incident wave from terminal A is divided into the same amplitude by the distributor 1,
It is split into waves with the same phase. Therefore, the incident wave is divided into four equal parts by the three dividers, and is incident on each of the four unit amplifiers 2 in the same phase.

Now, if the characteristics of the unit amplifiers 2 are uniform, the waves amplified by each unit amplifier 2 have the same amplitude and the same phase, so due to the reversibility of the divider 2, power is combined on the output side of terminal B. be done.

Therefore, even if the output of the unit amplifier 21 is small, by performing power combining using the distributor 1, a semiconductor amplifier with a large output can be obtained.

However, in this type of semiconductor amplifier, as the number of unit amplifiers 2 increases, the number of dividers 1 on the input/output side also increases, and the distance from input/output terminals A and B to the unit amplifiers 2 increases. Therefore, the loss of the distributor 1 and the connecting circuit increases, and there is a drawback that power cannot be effectively combined.

In order to solve this drawback, this invention converts the fundamental mode incident wave propagating through a waveguide into a higher-order mote using a mode converter, and amplifies this higher-order mode by coupling it with a plurality of unit amplifiers. The output wave of each unit amplifier excites the higher-order mode, and the mode converter converts the higher-order mode back into the fundamental mode that propagates through the output waveguide, and attempts to effectively synthesize the outputs of each unit amplifier. It is something.

FIG. 2 is a partially cutaway structural diagram showing an embodiment of the present invention. In the figure, 3 is a main waveguide, 4 is a sub-waveguide that propagates a higher-order mode coupled with the main waveguide,
Reference numeral 5 indicates a coupling hole for coupling radio waves of both the main and sub waveguides, and 6 indicates a non-reflection termination provided at one end of both the main and sub waveguides.

For convenience of explanation below, it is assumed that the size of the sub waveguide 4 is selected so that the TE ₃₀ mode propagates at the same phase velocity as the TE ₁₀ mode of the main waveguide 3.

Further, in Fig. 2, 7 is the conductor of the microstrip line, 8 is the dielectric substrate of the microstrip line,
2 is a unit amplifier having a microstrip line as an input/output line; 9 is a conductor plate for connecting the microstrip line and the sub-waveguide 4; Partially forming a tube.

Now, consider the case where an incident wave arrives at terminal A of main wave tube 3. This incident wave propagates through the main waveguide 3 in the fundamental mode, TE ₁₀ mode, and is coupled to the TE ₃₀ mode of the sub waveguide 4 via the coupling hole 5 . Since both modes have the same phase velocity, if the length of the coupling hole 5 is appropriately selected, the TE _{10 mode of the main waveguide 3 will be the same as the TE 10} mode of the sub waveguide 4, as is clear from the mode coupling theory.
Converted to TE ₃₀ mode.

FIG. 3 shows the electromagnetic field distribution in the cross section of the TE ₃₀ mode of the sub-waveguide 4. Solid arrows are electric lines of force, and dotted arrows are magnetic lines of force.

There are three locations within the cross section of the sub waveguide 4 where the electromagnetic field is strong. When a conductor plate 9 is provided at this position and a microstrip line conductor 7 is connected to each conductor plate 9, the TE ₃₀ mode is converted into three microstrip line waves transmitting equal power.

Therefore, by connecting the unit amplifier 2 to this microstrip line, the TE ₃₀ mode of the sub waveguide 4 can be amplified. In FIG. 2, since the TE ₁₀ mode is converted into the two sub-waveguides 4 that propagate the TE ₃₀ mode, the incident wave is amplified by six unit amplifiers 2.

In addition, the amplified wave is the incident wave of the sub-waveguide 4.
Through the reverse process of converting into TE ₃₀ mode and then converting into microstrip line wave, the microstrip line wave is converted into TE ₁₀ mode which propagates through main waveguide 3 and reaches terminal B. . In addition, although the propagation wave of the sub-waveguide 4 is set to the _TE30 mode in the above, it is clear that the TEno mode may generally be used. Here n is a positive integer. Furthermore, the number of sub waveguides 4 is not limited either.

As described above, in the semiconductor amplifier according to the present invention, the _TE10 mode is converted to the TEno mode, and the TEno
In order to obtain a large output by coupling the unit amplifier 2 to the mode, the number of unit amplifiers 2 can be adjusted by changing the size of the sub-waveguide 4 and selecting the mode that propagates through the sub-waveguide 4. This has the effect that power can be combined without using a large number of distributors 1 as in the device described above.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of the configuration of a conventional device of this type, Fig. 2 is a structural diagram showing an embodiment of the present invention with some parts cut out, and Fig. 3 is a diagram showing the electric current in the cross section of the sub-waveguide. It is an electromagnetic field distribution diagram showing the distribution of lines of force and magnetic lines of force. In the figure, 1 is a distributor, 2 is a unit amplifier, 3 is a main waveguide, and 4 is a sub waveguide. It should be noted that the same or corresponding parts in the figures are indicated by the same reference numerals.

Claims (1)

[Claims] 1. A semiconductor amplifier that combines the outputs of a plurality of unit semiconductor amplifiers, characterized in that the unit semiconductor amplifier is configured to couple with a TEno mode wave which is a higher order mode of a rectangular waveguide.