JPH01117401A - Coplanar circuit - Google Patents

Abstract

PURPOSE:To constitute the title circuit on a semiconductor substrate only by constituting a connection part between a coupling slot line and a coplanar line in a multi-layer structure. CONSTITUTION:A coplanar line 24 is formed in crossing with a connection point between coupling slot lines 41, 42 and connected to a conductor layer 27 constituting the coupling slot lines 41, 42 through a center conductor 25 and strip conductor 26. Moreover, conductors 28, 29 are connected by a conning piece 35 at the coupled part of the coupling slot lines 41, 42 and the coplanar line 24 by a connecting piece 35, furthermore center conductors 43, 44 of the coupling slot lines 41, 42 are connected by a connecting piece 45 and insulation layers 36, 46 are interposed between the connecting pieces 35, 45 and the bottom of slots at both sides of the strip line 26 and between them and the line 26. Thus, the circuit coupling the coplanar lien 24 and the coupling slot lines 41, 42 on a semiconductor substrate 21 is manufactured by the etching process only.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coplanar circuit that is used as a microwave circuit and is composed of coplanar lines.

[Prior art]

As shown in FIG. 1, a circuit constructed using a conventional coplanar line has a microstrip line 12 formed on one side of a dielectric substrate 11, and coupled slot lines connected to each other on the other side of the dielectric substrate 11. 13° 14 are formed, and the microstrip line 12 and the coupled slot line 13.14 are connected by the conductor 15 in the through hole provided in the dielectric substrate ll.
For example, the input wave from the boat 16 propagates through the microstrip line 12, and is propagated through the coupled slot line 13, 14 by the through-hole conductor 15 (
propagating in even mode), each boat 17.1
Output is obtained from 8.

The through holes in the dielectric substrate 11 are usually formed using a drill, laser, or the like. For this reason, there is a problem that high machining accuracy is required and manufacturing cost increases. Furthermore, when the operating frequency becomes high, the transmission characteristics deteriorate due to the parasitic elements of the through-hole conductor 15, so there is a limit to the applicable frequency. Furthermore, when this configuration is applied to a monolithic integrated circuit formed on a semiconductor substrate, the pattern must also be formed on the back side of the semiconductor substrate, which increases the number of etching steps and reduces the substrate size by using the back side. Due to this increase, it is difficult to realize economicalization and miniaturization of microwave circuits by making them monolithic.

[Purpose of the invention]

The object of the present invention is to provide a coplanar circuit that can be constructed only on a semiconductor substrate in order to eliminate these drawbacks.

〔Example〕

FIG. 2 shows an embodiment of the present invention, in which a conductor layer is formed on one surface of a semiconductor substrate 21, and coupling slot lines 41 and 42 are formed to substantially extend with respect to the conductor layer. A coplanar line 24 is formed by intersecting the connection points of 41° and 42, and a coupling slot line 41. -42 connection, and the coupled slot line 41.
42 and the conductor layer 2 on the opposite side to the coplanar line 24
Connected to 7. The width of the strip conductor 26 is the width of the center conductor 2
The width of the lines 41, 42 and 24 is made narrower than the width of 5, and the connection is made like a lumped constant to achieve impedance matching between the lines 41, 42 and 24. In addition, the slots 31 and 32 between the center conductor 25 and both outer conductors 28 and 29 of the coplanar line 24 are connected to the strip line 2.
A coupled slot line 41.4 is extended along both side edges of 6.
Grooves 33, 34 are formed so as to connect to 2. The conductors 28, 29 are connected by a connecting piece 35 at the joint between the combined slot line 41, 42 and the coplanar line 24,
Furthermore, the center conductor 43. of the coupled slot line 41.42.
44 are connected by a connecting piece 45, and for example, a Sin.

An insulating layer 36, 46 such as is interposed. Connecting piece 35.
The opposing area between the strip line 45 and the strip line 26 is made as small as possible to reduce the capacitance between them.

The ends opposite to the joints between the coupled slot lines 41 and 42 and the coplanar line 24 are connected to input/output boats 37 and 38, respectively.
．． It is said to be 39.

FIG. 3 is a diagram for explaining the operating principle of FIG. 2 using the propagation mode of the line. The direction 47 of the electric field in the propagation mode of the coplanar line 24 is directed from the center conductor 25 to the outer ground conductors 28, 29, and the potentials of the ground conductors on both sides are zero potential. Therefore, as shown in Fig. 3, even if the conductors on both sides are connected using the grounding piece 35, there is no effect on the propagation mode.In other words, the conversion part from the coplanar line to the coupled slot line uses this characteristic. There is. Since the center conductor 43.44 of the coupled slot line 41.42 is separated from the outer ground conductor 28.29 of the coplanar line 25, the coupling piece 45 does not affect the propagation mode of the coplanar line 25. .4
The electric field of 2 is in the direction shown by 4B. This indicates that the propagation mode of the coplanar line 25 is branched in parallel and then converted into an even mode of the coupled slot line. The even mode of the coupled slot line consists of components in the same electric field direction, and this circuit can also be called an even mode excitation circuit. By appropriately selecting the characteristic impedance of the coupled slot lines 41 and 42, the output capacitor) 37.
38 provides outputs of the same amplitude and phase.

FIG. 4 shows an equivalent circuit of FIG. 2. Combined slot line 4
1.42 and the coplanar line 24 are connected to each other. The coplanar line 24 is branched in parallel by coupled slot lines 41 and 42. The intersections between the strip line 26 and the connecting pieces 35, 45 are fabricated by etching, which is used in semiconductor technology, and a pattern can be created with high precision.

In addition, the thickness of the insulating layer 36.46 is set such that coupling between the lines is minimized, that is, the thickness of the strip line 26 and the connecting piece 35.4 is adjusted to minimize the coupling between the lines.
It can be manufactured so that capacitive coupling with 5 is small and parasitic elements due to discontinuities are minimized. Therefore, the circuit with this configuration is applicable to high frequency bands, and since only one side of the semiconductor substrate 21 is used,
Since the pattern can be manufactured by etching only one side, and since the connecting portion between the coupled slot lines 41, 42 and the coplanar line 24 is constructed with a multilayer structure, the dimensions of the circuit can be made sufficiently small. Therefore, there is an advantage that a monolithic integrated circuit can be realized in a high frequency band, which can achieve economicalization and miniaturization of the circuit. For example, in the case of a hybrid integrated circuit, the precision is on the order of tens of micrometers to several hundred micrometers, but with semiconductor manufacturing technology (etching technology), the precision can be less than 1 micrometer.

As described above, the coplanar circuit according to the present invention has the advantage that the circuit for coupling the coplanar line and the coupled slot line on a semiconductor substrate has a simple structure, has good high frequency characteristics, and can be manufactured using only an etching process. .

〔effect〕

As explained above, the coplanar circuit according to the present invention is constructed on a semiconductor substrate, and the coplanar line, that is, the coupling circuit between the coupled slot line and the coplanar line can be manufactured only by an etching process without machining, and furthermore, the pattern size Since the etching accuracy can also be specified with etching accuracy, it is possible to avoid parasitic elements, coupling between lines, etc., and therefore there is an advantage that it can be applied as a monolithic integrated circuit that achieves miniaturization and economicalization of microwave and millimeter wave circuits.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a conventional coplanar circuit, Fig. 2 is a perspective view showing an embodiment of the present invention, Fig. 3 is a diagram for explaining the principle of operation, and Fig. 4 is an equivalent circuit thereof. . 21... Semiconductor substrate, 24... Coplanar line, 2
5... Center conductor of coplanar line, 26... Strip conductor, 35.45... Connecting piece made of strip conductor on insulating layer, 36.46... Insulating layer, 37.38
. 39... Input/output boat, 41.42... Coupled slot line, 47.48... Direction of electric field.

Claims (1)

[Claims] (1) A coupled slot line is formed on the semiconductor substrate by first, second and third conductor layers, a coplanar line is formed on the semiconductor substrate, and the center conductor of the coplanar line is connected to the first conductor layer. The two outer conductors of the coplanar line are connected to the third conductor layer, and an insulating layer is interposed between the connection portion between the center conductor and the first conductor layer and the second and third conductor layers. coplanar circuit.