JPS61198902A - Hybrid - Google Patents

Abstract

PURPOSE:To simplify the circuit form of a transmission line by connecting a line having a length of nearly (2n-1)lambda/2 and one absorbing resistor in series between the 1st output terminal and the 2nd output terminal. CONSTITUTION:One input terminal IN and two output terminals OUT1, OUT2 are provided. A transmission line L1 having a length of (2n-1)lambda/4 is connected between the input terminal In and the 1st output terminal OUT1. The (2n-1)lambda/4 is a value of an electromagnetic wave propagating through the line L1 at its center frequency, where n=1, 2... is a wavelength. A transmission line L2 having a length of (2n'-1)lambda/4 (where; n'=1, 2...) is connected between the input termi nal IN and the 2nd output terminal OUT2. Further, a transmission line L3 having a length of (2n''-1)lambda/2 (where; n''=1, 2...) and the absorbing resistor R are connected in series between the 1st output terminal OUT1 and the 2nd output terminal OUT2. Thus, the phase of the electromagnetic wave outputted from the 1st and 2nd output terminals is shifted by 180 deg. and the coupling with the input terminal IN has a gain of 3(dB).

Description

[Detailed Description of the Invention] [Summary] This is a hybrid that branches input power into powers with different phases, and the distance between the first output terminal and the second output terminal is approximately (
2nd) A line of length 2 and one absorption resistor are connected in series to simplify the circuit configuration of the transmission line.

[Industrial application field]

The present invention relates to a hybrid that branches electromagnetic waves input from one input terminal into a first output terminal and a second output terminal.

In general, hybrids used for transmission lines such as microstrip lines have a
Absorption resistance is provided.

That is, an absorption resistor is required to eliminate reflected waves and reduce the standing wave ratio.

[Conventional technology]

As shown in FIG. 5, the conventional hybrid has a line 11 between the input terminal in and the first output terminal out 1, a line 12 between the input terminal in and the second output terminal out 2, and a line between the first and second output terminals. Outs 1 and 2 are connected to each other by a line 13 with a pH of 4, and an absorption resistor r with one end grounded is provided at the connection point between the brackets 13 and 14.

The hybrid shown in Figure 5 is 1 when the impedance of the signal source and load is Zo, and the wavelength of the electromagnetic wave to be transmitted is λ.
It is an 80° hybrid. The above 11 has a length of 3λ/4,
The characteristic impedance '2Zo, 12p13p14 is the length λ/4, and the characteristic impedance '2 Zo, r is the impedance related to the terminals in and out Lout 2 at the center frequency, and the compression (coupling degree) between the terminals outl and 2. It has the role of reducing to zero.

By the way, when transmitting high frequencies, such as microwaves of 10G82 or higher, by forming a transmission line with a long and thin strip line using the circuit shown in Fig. 5, the impedance of the ground circuit will decrease due to the presence of parasitic inductance and resistance of the conductor. It is difficult to make it zero.

Therefore, in the past, the absorption resistance r was calculated using a λ/4 line, a 1×2 line as shown in Fig. 6(A) and λ(B), or a 1×2 line as shown in Fig. 7(C).
An attempt was made to reduce the impedance of the ground circuit to zero by combining it with a fan-shaped line of radius λ/4 like this.

In this way, by providing an absorption resistor in combination with a line with one end open (open stub), the impedance of the ground circuit can be reduced to zero from a high frequency perspective.

[Problem that the invention seeks to solve]

However, if the absorbing resistor portion is configured as shown in FIG. 6, the device will become larger only by the open-ended line.

Therefore, when the hybrid is used in a mixer circuit, there is a problem that the absorbing resistor portion becomes a hindrance.

Further, in the configuration shown in FIG. 6, electromagnetic waves leak from the open end.

For this reason, there is a problem that the characteristics of other circuits coupled to the hybrid are degraded and that oscillation occurs when amplifying elements are mixed.

[Means and effects for solving the problems] The present invention solves the above problems, and the absorption resistor part has a simple shape and can be miniaturized, and there is no leakage of electromagnetic waves and less coupling with other circuits. The purpose is to provide a hybrid, and the circuit is simple and compact by connecting an absorption resistor and a λ/2 length line in series between the first output terminal and the second output terminal. At the same time, there is no leakage of electromagnetic waves, so the absorption resistor part no longer gets in the way, and electromagnetic coupling with other circuits can be reduced.

〔Example〕

Hereinafter, the present invention will be explained by way of examples with reference to the accompanying drawings.

FIG. 1 is a diagram showing the configuration of a hybrid according to the present invention.

The hybrid shown in FIG. 1 has one input terminal IN and two output terminals, namely a first output terminal 0UTI and a second output terminal ou'r2.

A transmission line L1 having a length of λ (2n-1) 4 is connected between the input terminal IN and the first output terminal 0UTj.

λ (2n-1) above, i- is the value at the center frequency of the electromagnetic wave propagating through the transmission line L1, n=1°2,
..., λ is the wavelength. Hereinafter, lengths corresponding to this expression are used with the same meaning.

There is a length of 2 between the input terminal IN and the second output terminal 0UT2.
n'-1)'(n' = 1, 2...) transmission lines L2 are connected.

Also, between the first output terminal 0UT1 and the second output terminal ou'r2, there is a length of 2n"-1)"(n" = 1, 2
-) transmission line L3 and absorption resistor R are connected in series.

The relationship between n and n' above is such that when the phase difference between the electromagnetic waves output from the first output terminal 0υT1 and the electromagnetic waves output from the second output terminal 0υT2 is 180°, I
By configuring as above, the phase difference between the electromagnetic waves output from the first output terminal outt and the second output terminal 0UT2 can be set to 180.
°, and input terminal IN and output terminal 0UT1,
The coupling between OUT2 can be 3 [dB].

That is, the lengths of the lines L2 and L3 in FIG. 1 are each 3. J 7 j Characteristic impedance is 4
．． 4,2, 12 Zo, and the characteristic diagram when the absorption resistance value is ZO is shown in FIG.

The horizontal axis in FIG. 2 shows the normalized frequency using a common scale. A normalized frequency is a multiple of some reference frequency. In this embodiment, the reference frequency is 1 (Gllz).

The first line on the vertical axis in Figure 2 is the coupling, that is, the input terminal IN.
Output terminal 0UT1 for the electromagnetic wave power input from
, the ratio of the power of electromagnetic waves output from 0UT2 is displayed in d8 units. Note that or indicates the direction in which the scale of each characteristic is viewed.

・The mark represents the coupling between the input terminal and the first output terminal 011T1, and the X mark represents the coupling between the input terminal and the second output terminal 0UT2.The ideal value is 3 (dB), but this degree of change If so, the function as a hybrid will not be impaired in any way.

The second vertical axis represents the phase difference between the electromagnetic waves output from both output terminals 0UT1 and 0UT2, and the number of central stations S is 1 (
Gllz) and 180°.

The third value on the vertical axis represents the isolation from the first output terminal 0UT1 to the second output terminal 0UT2 in small dB units, and the smaller this value is, the less the reflection is.

The fourth axis on the vertical axis represents the standing wave ratio (VSWR), where the Δ mark is the input terminal IN, and the * mark is the first output terminal 011T1.
, the X mark relates to the second output terminal 011T2.

As described above, unlike the prior art, a hybrid is constructed by connecting a transmission line and an absorption resistor in series between output terminals, but its characteristics are not degraded and can operate over a high frequency range.

In Figure 3, the absorption resistance is ZO, and the line L1 in Figure 1 is 1
．． 34Zo, L2 1.36Zo, L3 1.26
Z.

It is a characteristic diagram when it sets to.

In addition, in FIG. 4, the length of Ll in FIG. 1 is −L L
The length of 2 is 1. If other conditions are the same, 4.
4. It is a characteristic diagram of .

〔Effect of the invention〕

As described above, according to the present invention, by connecting the absorption resistor and the λ/2 length line in series between the first output terminal and the second output terminal, the circuit becomes simple and compact. Since there is no leakage of electromagnetic waves, the absorption resistor part does not get in the way (and electromagnetic coupling with other circuits can also be reduced).

[Brief explanation of drawings]

Figure 1 is a configuration diagram of the hybrid of the present invention, Figures 2 to 4
The figure is a characteristic diagram of FIG. 1, FIG. 5 is a block diagram of a conventional hybrid, and FIG. 6 is an enlarged view of the absorption resistance portion of FIG. L 1p L2 p L3...Transmission line, R...
...absorption resistor, IN ...input terminal, OUT 1 ...first output terminal, 0UT2 ...
...Second output terminal. OUT2 Configuration diagram of the hybrid of the present invention Fig. 1 → Standardized frequency Fig. 3 Invention 2, ear "J y )". Characteristic.

Claims (1)

[Claims] A hybrid configured by an electromagnetic wave transmission line, in which the electromagnetic wave input from an input terminal is branched and output from a first output terminal and a second output terminal, respectively, wherein the wavelength of the electromagnetic wave is λ, positive Let n, n', n'' be the integers of A transmission line having a length of (2n'-1)λ/4 at the center frequency is connected between the second output terminals, and a transmission line having a length of (2n'-1)λ/4 at the center frequency is connected between the first and second output terminals. A hybrid characterized in that a transmission line with a length of (2n''-1)λ/2 and an absorption resistor are connected in series.