JP3051430B2 - Microwave integrated circuit - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to coplanar and uniplanar microwave integrated circuits (MICs).

The present invention can be applied to a monolithic microwave integrated circuit (MMIC).

[Conventional technology]

Conventional microwave integrated circuits mainly use a configuration using a microstrip line.

On the other hand, microwave integrated circuits using coplanar waveguides (M. Riaziat et al, “Coplanar waveguides fo
r MMICs ", Microwave Journal, pp. 125-131, June 198
7) Alternatively, uniplanar microwave integrated circuits aiming at higher integration (literature, M. Muraguchi et al, “Unip
lanar MMICs and their applications ", IEEE Trans.Mic
rowave Theory Tech., vol.MMT-36, pp. 1896-1901, Dec.
1988) has also been proposed.

These coplanar and uniplanar microwave integrated circuits have a high-frequency ground (ground conductor) on the surface of the circuit board, eliminating the need for via holes for grounding, and have a small circuit area and high integration. It has features that are easy to do. Therefore, such a microwave integrated circuit has become a promising integrated circuit for reducing the size, weight, and cost of microwave radio devices and other devices.

[Problems to be solved by the invention]

FIG. 3 shows a configuration example of a conventional microwave integrated circuit having a high-frequency ground on a circuit board surface.

As shown in the drawing, reference numerals 31 and 32 are circuit boards 33, respectively.
The input terminal and the output terminal of the circuit element 34 formed thereon. When such a circuit element 34 is mounted on a package, chassis or other conductive substrate, a floor ground 36 is formed in addition to the surface ground 35. The circuit element 34 is
A transistor and other active elements, a resistor, a capacitor, an inductor and other impedance matching elements, and a bias circuit element are integrated. The bias circuit element is mounted in a state surrounded by the surface ground 35 two-dimensionally.

Each of the input / output terminals 31 and 32 has a coplanar line structure including a center conductor electrically connected to the circuit element 34 and ground conductors on both sides constituting a part of the surface ground 35. The input / output terminals 31 and 32 are provided with conductor bridges 37 and 38 for connecting the ground conductors on both sides.

In such a configuration, a microwave signal input from another circuit propagates through the coplanar line of the input terminal 31 and is supplied to the circuit element 34, and the circuit element 34 performs predetermined signal processing (amplification and frequency conversion). After that, the signal propagates through the coplanar line of the output terminal 32 and is output to another circuit.

By the way, in such a structure, the surface ground 35 and the floor ground 36 have a microstrip line structure. Therefore, if there is a high frequency difference between the potential of the floor ground 36 to which the circuit board 33 is attached and the potential of the surface ground 35 of the circuit board 33, the surface ground 35 causes a microstrip mode resonance phenomenon. It is known. The dimensions of the surface ground 35 are several cm in the case of a microwave integrated circuit, several mm in the case of a monolithic microwave integrated circuit, and since the dielectric constant of the circuit board 33 is about 10, the surface ground 35 has a frequency of several GHz. A standing wave is generated on the ground 35. That is, the surface ground 35 becomes a resonator having a half wavelength (or an integral multiple thereof).

However, it is difficult to eliminate this resonance phenomenon. For example, as shown in FIG. 4, a gold wire 41 or a gold ribbon is used to form a surface ground 35 and a floor ground.
Although a method of short-circuiting with 36 has been attempted, the short-circuit connection can be made only at the edge of the circuit board 33. Therefore, a microstrip mode electric field is generated near the center of the circuit board 33, and the occurrence of a resonance phenomenon is inevitable for frequencies at which the board dimensions are about half a wavelength.

Such a resonance phenomenon causes remarkable deterioration in the frequency characteristics of the microwave integrated circuit. For example, when a microwave integrated circuit is used as an amplifier, a peak or a dip appears in the frequency characteristic of the gain, and unnecessary oscillation may occur.

As described above, near the resonance frequency, the frequency characteristic of the impedance viewed from the input terminal 31 or the output terminal 32 becomes steep, and in order to obtain a flat frequency characteristic over a wide band, the resonance due to this standing wave must be suppressed.

In order to solve such a problem, conventionally, gold wires and other connection points are adjusted for each circuit so that the resonance does not enter the used band. However, such adjustment can be dealt with when the microwave integrated circuit is used in a narrow band, but it has been difficult to realize a microwave integrated circuit that can be used in a wide band.

SUMMARY OF THE INVENTION An object of the present invention is to provide a microwave integrated circuit which retains the features of a coplanar type or a uniplanar type with a high degree of integration, and can obtain good frequency characteristics over a wide band.

[Means for solving the problem]

According to the first aspect of the present invention, a circuit element is integrally formed on a circuit board having a predetermined thickness, a surface ground is provided on a surface of the circuit board, and a floor ground is provided on a board on which the circuit board is mounted. A microwave integrated circuit having a coplanar line structure or a uniplanar line structure at input and output ends of the circuit element, wherein a high frequency Q dump circuit is inserted and connected between the surface ground and the floor ground. I do.

According to a second aspect of the present invention, in the microwave integrated circuit according to the first aspect, the Q dump circuit is integrated with a circuit element on the same circuit board.

(Operation)

In the present invention, the Q dump circuit that connects the surface ground and the floor ground operates as an attenuation circuit or an absorption circuit against an electric field in the microstrip mode.

Therefore, since the microwave in the microstrip mode that has propagated through the gap between the surface ground and the floor ground is terminated by this Q dump circuit, reflection at the surface ground is suppressed, and the standing wave is suppressed to suppress the resonance phenomenon. Can be suppressed.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the configuration of an embodiment according to the first aspect of the present invention.

Note that the same components as those in the related art shown in FIG. 3 are denoted by the same reference numerals and description thereof will not be repeated.

In FIG. 1, in this embodiment, a resistor 11 is connected from a surface ground 35 to a floor ground 36 as a Q dump circuit. Note that the resistance value of the resistor 11 is set to a value close to the characteristic impedance of the microstrip mode (normally, about several tens of ohms). Such a resistor 11 terminates the microwave in the microstrip mode that has propagated in the gap between the surface ground and the floor ground, and
We suppress reflection in 35. That is, the resistor 11 operates as a mode-selective Q dump circuit, and can suppress the resonance phenomenon.

The resistance value of the resistor 11 has a large effect when the resistance value is close to the characteristic impedance in the microstrip mode, but is not necessarily limited thereto.

FIG. 2 shows an embodiment of the invention according to claim 2.

Note that the same components as those in the related art shown in FIG. 3 are denoted by the same reference numerals and description thereof will not be repeated.

In FIG. 2, in this embodiment, a resistor for connecting a surface ground 35 and a floor ground 36 is used as a Q dump circuit.
21 is integrated and formed on a circuit board 33. Further, the conductor pillar 23 having a thickness substantially equal to that of the circuit board 33 and being connected to the floor ground 36 is arranged at a position close to the resistor 21, and one end of the resistor 21 having one end connected to the surface ground 35. The other end is connected by a plurality of short gold wires 25.

In such a structure, since the parasitic inductance of the Q dump circuit is smaller than that of the example shown in FIG. 1, it is easy to realize a wide band characteristic in a higher frequency band.

In the above-described embodiment, the resistors 11 and 21 are connected to the corners of the surface ground 35.However, a sufficient effect can be obtained if the standing wave voltage is high, not limited to the corners. Can be. Further, a plurality of resistors may be provided at a plurality of locations.

When it is desired to make a direct current conduction between the surface ground 35 and the floor ground 36 in addition to the resistor as the Q dump circuit, a configuration in which a resistor and an indunk are connected in parallel is effective. When it is desired to insulate DC from the floor ground 36 in a DC manner, a configuration in which a resistor and a capacitor are connected in series is effective. Further, these circuits may be used in combination.

The resistor used in the Q dump circuit may be either a lead wire type or a chip type.

〔The invention's effect〕

As described above, the present invention has a good frequency characteristic in a wide band when a coplanar or uniplanar type microwave integrated circuit is mounted on a package or the like, without impairing the ultra-compact features associated with high integration. A microwave device can be realized.

Therefore, it is possible to contribute to a reduction in size, weight, and cost of a general-purpose microwave measuring device, a radar device, and other devices requiring a wide frequency band characteristic.

[Brief description of the drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of the invention described in claim 1. FIG. 2 is a diagram showing the configuration of an embodiment of the invention described in claim 2. FIG. 3 is a diagram showing a configuration example of a conventional microwave integrated circuit having a high-frequency ground on the surface of a circuit board. FIG. 4 is a diagram showing a configuration example for eliminating a resonance phenomenon in a conventional microwave integrated circuit. 11, 21 ... resistor, 23 ... conductor pillar, 25 ... gold wire, 31
…… Input terminal, 32 …… Output terminal, 33 …… Circuit board, 34…
… Circuit element, 35… Ground surface, 36… Ground floor,
37, 38: Conductor bridge, 41: Gold wire.

Continuation of front page (72) Inventor Masahiro Muraguchi 1-6-1, Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References Japanese Unexamined Patent Publication No. Sho 63-209309 (JP, A) (JP, U) Japanese Utility Model Showa 64-51303 (JP, U) Japanese Utility Model Showa 62-84204 (JP, U) Muragucgchi et al. "Uniplanar MMIC's and Their Applications," IEEE Transactions on Microwave Theory and Tech nikques, Vol 36, pp. 1896-1901, Dec. 1988 (58) Surveyed fields (Int.Cl. ⁷ , DB name) H01P 1/162 H01P 1/22-1/24 H01P 3/08 H01P 5/02-5/08 H01L 27/04

Claims (2)

(57) [Claims] A circuit element is integrated on a circuit board having a predetermined thickness, a surface ground is provided on a surface of the circuit board, and a floor ground is provided on a board on which the circuit board is mounted.
In a microwave integrated circuit having a coplanar line structure or a uniplanar line structure at input and output ends of the circuit element, a high frequency Q dump circuit is inserted and connected between the surface ground and the floor ground. Microwave integrated circuit. 2. The microwave integrated circuit according to claim 1, wherein the Q dump circuit is integrated on the same circuit board as the circuit elements.