JPS583403B2 - Slot coupled line type MIC magic T - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a Magic T, and more particularly to the structure of a Magic T that is incorporated into an MIC (microwave integrated circuit).

The one shown in FIG. 1 is known as a conventional MIC Magic T.

Here, the dotted line is a slot line formed by a ground conductor provided on the back side of the dielectric substrate, and the solid line is a microstrip line formed by an elongated conductor provided on the front side of the substrate opposite to the ground conductor.

In FIG. 1, a microstrip line 8 is provided perpendicularly to the slot-coupled line 5 in order to excite the slot-coupled line 5 in an even mode, and an odd number multiple of a quarter wavelength is used to excite the slot-coupled line 5 in an odd mode. A microstrip line 9 is provided perpendicularly to the slot line 6 along with a quarter-wavelength open-ended line 10.

The odd mode excitation circuit of the slot coupled line 5 is configured in this way, and in order to provide the microstriped slot conversion circuit 10, the length of the slot line 6 is required to be approximately three times the quarter wavelength. , 4 and isolation characteristics between ports 3 and 4 become narrower, and the circuit configuration becomes larger.

Therefore, the characteristics of the circuit shown in FIG. 1 as a MIC Magic T were not necessarily good.

Therefore, an object of the present invention is to improve the above-mentioned drawbacks of the prior art, and its features include a slot coupling line constituted by a groove formed in a ground conductor formed on one side of a single dielectric substrate; On the other side of the board, a microstrip line composed of a long and thin conductor is provided orthogonally to the slot-coupled line, and the ground conductor of the slot-coupled line is short-circuited at a distance of an odd multiple of 1/4 wavelength from the orthogonal part. one end of the microstrip line is a first input/output port, a coplanar line provided at the extended end of the shorting piece of the slot coupled line is a second input/output port, the other end of the slot line is a third input/output port, and the other end of the slot line is a third input/output port. The fourth input/output port is in the magic T position.

Examples will be described below with reference to the drawings.

FIG. 2A shows an example of the structure of the magic T according to the present invention,
The dotted line line is a slot line formed by a groove formed in a ground conductor provided on the back side of the dielectric substrate, and the solid line line 10 is a microstrip line formed by an elongated conductor formed on the front side of the board facing the ground conductor. It is.

1, 2, 3.4 are input/output ports, 8 is an input/output microstrip line, 10 is a 1/4 wavelength microstrip line with an open end (the length l from the center of the slot coupled line to the tip is 1/4 wavelength), and 5 is a slot coupling line.

Here, the term "slot coupled line" refers to a line in which two slot line grooves are provided close to each other and are coupled to each other.

Reference numeral 11 denotes an input/output coplanar line, which is a line in which the central conductor of the slot-coupled line is the center conductor, and the conductors at both ends are ground conductors.

12 is a slot coupling line with a length that is an odd number times a quarter wavelength;
13 is a shorting piece (consisting of a ribbon or wire).

FIG. 2B is a sectional view taken along the line A-A' in FIG.
7 is a groove formed in the ground conductor.

As shown, the ground conductor is short-circuited by a short-circuit piece 13 across the groove.

Note that the position where the short-circuit piece is provided is a distance that is a na number times 1/4 wavelength from the center of the orthogonal part with the strip line.

The input from port 1 excites the slot coupled line in an odd mode and does not propagate to port 2, but is propagated in phase to ports 3 and 4 as shown in FIG. 3A.

In addition, the input from port 2 excites the slot-coupled line in an even mode, but because of the shorting piece 13, the port 1 side is in an open state from the tip short-circuited 1/4 wavelength line 12, and does not propagate to port 1. As shown in FIG. 3B, the signals are propagated to ports 3 and 4 in opposite phases.

The arrows in FIG. 3 schematically indicate the direction of the electric field.

Therefore, the slot line 6, which is required to be about 3/4 wavelength in the structure of FIG. 1, is replaced with the slot coupled line 12 of 1/4 wavelength in FIG. 2, and the circuit configuration is miniaturized. Furthermore, the isolation between the negative phase distribution ports 3 and 4 is also widened.

As explained above, the Magic T of the present invention uses a short-circuit conductor to eliminate the conventional slot line of an odd number multiple of a quarter wavelength.
, 4 can be achieved over a wide band, and the circuit configuration can be made smaller.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional magic T, Fig. 2A is a block diagram of a magic T according to the present invention, Fig. 2B is a sectional view taken along the line AN in Fig. 2A, and Figs. FIG. 2 is an explanatory diagram of the operation of the magic T shown in FIG. 2A. 1, 2, 3, 4; Input/output port, 5, 12; Slot coupling line, 6, 7; Slot line, 8, 9, 10; Microstrip line, 11: Coplanar single line, 13; Shorting piece, 14; Direction of electric field.

Claims (1)

[Claims] 1 A slot-coupled line formed by a groove formed in a ground conductor formed on one side of a single dielectric substrate, and a slender conductor formed perpendicularly to the slot-coupled line on the other side of the substrate. It has a microstrip line configured with a shorting piece that short-circuits the ground conductor of the slot coupled line at a distance of 1/4 wavelength from the orthogonal part, and one end of the microstrip line is connected to the first input/output port and the slot coupled line is connected to the first input/output port. A slot-coupled line type MIC magic T characterized in that a single coplanar line provided at the extended end of a shorting piece is used as a second input/output port, and the other ends of the slot line are used as third and fourth input/output ports.