JPS6216567B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transducer that performs conversion between a rectangular waveguide and a coaxial line, a strip line, or a microstrip line, and in particular has a function of absorbing unnecessary waves in addition to the conversion function. The present invention aims to provide a transducer having the following features.

In recent years, coaxialization has been introduced in high frequency signal transmission lines.
As MIC technology progresses, transducers are often used to connect to conventional waveguide circuits. As an example, the circuit configuration of a quasi-millimeter wave band amplifier with rectangular waveguide input and output is shown in FIG. In the figure, 1
and 2 is a transducer, 3 is an amplifier, a,
a' is a waveguide input/output end, and 4 and 4' are coaxial lines.

FIG. 2 shows a specific example of the conventional structure of the coaxial waveguide transducer shown in FIG. In FIG. 2, a indicates a waveguide terminal, b a coaxial terminal, 11 a rectangular waveguide, 12 a waveguide short, 13 a coaxial line, and 14 a coaxial line center conductor. A signal is input (or output) from terminal a and output (or input) from terminal b.

In the circuit shown in FIG. 1, a quasi-millimeter wave band signal input from terminal a passes through coaxial waveguide transducer 1, is amplified by amplifier 3, passes through coaxial waveguide transducer 2, and passes through the terminal. Output from a′.

However, the coaxial waveguide transducers 1 and 2 connected to the amplifier 3 are usually matched only within the waveguide usage band. In other bands, as is clear from Fig. 2, since the end of the coaxial line center conductor 14 is open, the impedance viewed from the input or output side of the amplifier 3 becomes pure reactance, and at certain frequencies, especially at low The frequency has entered an unstable region and is prone to abnormal oscillation. Note that in some conventional transducers, the end of the coaxial line center conductor is short-circuited within the waveguide, but the above points remain unchanged, and this will not change as long as conventional transducers are used. This is an unavoidable drawback.

The present invention aims to provide a transducer that eliminates these drawbacks.

The present invention provides two or more coaxial lines in a rectangular waveguide,
In a transducer to which a strip line or microstrip line is connected,
The center conductors of at least two of the connected lines are connected to each other in a rectangular waveguide, and the center conductor has a filter connected to a terminator in at least one of the connected lines. This is a transducer that uses

Examples of the present invention will be described below.

FIG. 3 shows a specific structural example of a coaxial waveguide transducer having a low-pass filter as an embodiment of the present invention. The same parts as in Figure 2 are numbered the same, 15 is a coaxial low-pass filter,
16 is a coaxial terminator, and the center conductor of the coaxial line 13 and the center conductor of the coaxial low-pass filter 15 are connected to the waveguide 1.
Connected within 1.

The coaxial low-pass filter 15 is designed to block the band used by the waveguide 11, and its electrically equivalent short-circuited surface or open surface is selected at an arbitrary position in the waveguide, and the coaxial low-pass filter 15 is designed to block the band used by the waveguide 11. Coaxial line 13 is matched. This allows terminal a (or b)
The signal in the waveguide usage band input from terminal b
(or a), and has the same function as a conventional transducer.

Furthermore, it is clear that outside the usage band of the waveguide, if a passband signal of the low-pass filter 15 is inputted from the terminal b, the signal is not output to the terminal a side but is absorbed by the terminator 16.

By the way, in this embodiment, a low-pass filter is used as the filter 15, but this filter is not limited to low-pass filters as long as it blocks the signal band converted from terminal a to b or from terminal b to a. Even if it is a band-elimination filter, a band-pass filter, or even a high-pass filter, the function as a transducer remains the same.

FIG. 4 shows a specific structural example of a microstrip waveguide transducer having a low-pass filter as a second embodiment of the present invention.

The differences from the embodiment shown in FIG. 3 are a microstrip line 23, a center conductor 24, a microstrip low-pass filter 25, and a dielectric substrate 26.
It is clear that there is no difference in the function as a transducer, and the function is also the same in a stripline waveguide transducer when the thing connected to the waveguide is a stripline.

Based on the above, in a transducer between a rectangular waveguide and a coaxial line, microstrip line, or strip line, a combination of a low-pass filter, a band-stop filter, a band-pass filter, or a high-pass filter is used. It will be understood that it is possible to realize a transducer having the functions of the present invention.

Now, when the transducer according to the present invention shown in FIG. 3 is used in the amplifier circuit shown in FIG. Because of this, the circuit seen from the amplifier can be matched over the entire frequency range, and unstable regions can be eliminated, making it possible to prevent abnormal oscillation, which was a drawback of the conventional method.

[Brief explanation of the drawing]

Fig. 1 shows an example of the configuration of an amplifier circuit using a conventional transducer, Fig. 2 shows an example of the structure of a conventional transducer, Fig. 3 shows an example of the structure of the first embodiment of the present invention, and Fig. 4 is a structural example of the second embodiment of the present invention. In the figure, a, a'... waveguide input/output terminal, b
... Coaxial terminal, 1, 2 ... Coaxial waveguide transducer, 3 ... Amplifier, 11 ... Waveguide, 12 ...
...Waveguide shot, 13...Coaxial line, 14...
Coaxial line center conductor, 15... coaxial low-pass filter,
16...Terminator, 23...Microstrip line, 24...Microstrip center conductor, 25
...Microstrip low-pass filter, 26...
It is a dielectric substrate.

Claims (1)

[Claims] 1. In a transducer in which two or more coaxial lines, strip lines, or microstrip lines are connected to a rectangular waveguide, the center conductors of at least two of the connected lines are connected to each other in the rectangular waveguide. A transducer comprising a filter connected within a waveguide and having a terminator connected to at least one of the lines to which the center conductor is connected.