JPH02202702A - Microwave circuit - Google Patents

Abstract

PURPOSE:To reduce the overall size of a microwave circuit by adding a circuit consisting of a coplanar line on one of both sides of a dielectric substrate with a circuit consisting of a microwave strip line and using its earth electrode surface of a coplanar line as a lower earth surface added to the other side of the dielectric substrate respectively. CONSTITUTION:A microwave circuit uses an earth electrode surface 20 of a coplanar line to form a microstrip line on its counter surface 23. Then the filters 13, 14 and 17 and an intermediate frequency short circuit line 16 are formed with the microstrip line on the surface 23. At the same time, an amplifying FET 12, an image signal eliminating filter 13, etc., are formed on a coplanar line surface 24 containing an earth electrode surface 20. In such a constitution, the circuits can be decentralized on both sides of a dielectric substrate 19. Thus the overall size can be reduced for a microwave circuit.

Description

[Detailed Description of the Invention] Dermatological Epitheliology Department! The present invention relates to a microwave circuit that configures a circuit on a dielectric substrate surface.

In recent years, with the rapid development of satellite communication systems, there has been an extremely high demand for higher performance, greater integration, and miniaturization of the microwave circuits that play an important role as the transmitter and receiver. .

Strip lines are commonly used in microwave band circuits, and FIG. 3 shows an example of a conventional circuit from the first-stage low-noise amplifier to the mixer section of a down converter for satellite communication reception. In the figure, 1 is an input matching circuit using a microstrip line in the final stage of the low-noise amplifier.

2 is an amplification FET (field effect transistor), 3 is an image signal removal filter 54, a band pass filter for local oscillation signals, 5 is a mixing diode, 6 is an intermediate frequency short circuit, 7 is a 0-lotus filter for intermediate frequencies, 8 is a grounding via hole, and 9 is a dielectric substrate. This conventional example is a so-called MMIC that is monolithic on a semiconductor substrate.
(monolithic microwave IC), but the same situation applies to hybrid ICs using an alumina substrate or the like.

In the conventional example mentioned above, various filters 3, 4, 6, and 7 degrees occupy the main area on the circuit, so in order to reduce the size of the entire circuit, Naturally, these filters need to be miniaturized.

By the way, when configuring a filter with strip lines,
The length of the line must be about A, which is the wavelength of the desired frequency on the strip line.Therefore, the method of reducing the area of the filter is to make the substrate thinner and narrow the width on the strip line, or to reduce the dielectric constant. The only way is to shorten the wavelength on the strip line by using a large substrate. However, it is not possible to make the substrate very thin due to handling reasons, and it is extremely difficult to obtain a substrate with a high dielectric constant and low loss. Particularly when attempting to implement MMIC, the passive element section becomes much larger than the active element section, resulting in the disadvantage that the advantages of MMIC implementation are lost.

The present invention has been made in view of these points, and it is an object of the present invention to provide a novel microwave circuit which eliminates the above-mentioned drawbacks.

In order to achieve the above-mentioned object, the microwave circuit of the present invention has a circuit composed of a coplanar line on one side of a dielectric substrate, and a grounding circuit of the coplanar line on the other side. It has a circuit consisting of a microstrip line with the electrode surface as the lower ground plane.

With this configuration, microwave circuits can be configured on both sides of the board, and a microstrip line circuit can be configured on the other side using the ground electrode surface of the coplanar line, making effective use of the board surface. Therefore, the microwave circuit can be made smaller accordingly.

Back 1st group Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show a microwave circuit according to an embodiment of the present invention.

In FIG. 1, numeral 11 is an input matching circuit using a coplanar line (lla) in the final stage of the low-noise amplifier. Here, the shaded area 20 is the ground electrode surface of the coplanar line, and the opposing surface 2
The microstrip line on 3 is indicated by a broken line. 1
2 is an amplification FET, 13 is an image signal removal filter,
14 is a band pass filter for local oscillation signals, 15 is a mixing diode 116 is an intermediate frequency short circuit line, 17 is a low pass filter for intermediate frequencies, 1B is a via hole for grounding, and 19 is a dielectric substrate.

21 is a bump for flip-chip mounting, and 22 is a through hole for wiring between the front and back surfaces. In addition, in Figure 2, -dotted chain line A-
It shows a cross-sectional view between B and the reference numerals in the drawing represent the same reference numerals as those in FIG. 1.

As can be seen from FIGS. 1 and 2, in this embodiment, a microstrip line is formed on the opposing surface 23 by using the ground electrode surface 20 of the coplanar line. The filters 13, 14, 17 and the short circuit line 16 are formed as microstrip lines on the opposing surface 23, and the FET 12° is formed on the coplanar line surface 24 having the other electrode surface 20. The diode 13 and the like.

Since the circuits can be distributed on both sides of the dielectric substrate 19 in this way, the overall size of the circuit can be reduced. still,
A ground electrode surface 20 of the dielectric substrate 19 is electrically connected and mechanically coupled to a grounding conductor plate 25 via a bump 21.

Although the present embodiment has been described using a down converter for satellite communication reception, it goes without saying that the present invention can be effectively applied to other microwave circuits.

As described above, according to the present invention, the substrate surface can be effectively utilized, so that the microwave circuit can be constructed in a compact size.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a microwave circuit embodying the present invention, and FIG. 2 is a sectional view taken along the line A--B in FIG. 1. Third
The figure is a configuration diagram of a conventional microwave circuit. 11... Input matching circuit, 12... - FET for amplification. 13- Image signal removal filter. 14-Bandpass filter for local oscillation signal. 15.--Mixing diode. 16-Intermediate frequency short circuit line. 17.--Intermediate frequency band pass filter. 18-- grounding via hole, 19- dielectric substrate. 20 - Ground electrode surface for coplanar line. 21-・Bump for flip chip mounting. Front and back surfaces facing through-holes for wiring, 24-... coplanar track surface. Embedded by Ganto Sharp Co., Ltd.

Claims (1)

[Claims] (1) A dielectric substrate has a circuit composed of a coplanar line on one side, and a circuit composed of a microstrip line whose lower ground plane is the ground electrode of the coplanar line on the other side. Features microwave circuit.