JPH11346129A - Microwave amplifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a microwave amplifier of a small size with wideband frequency characteristic. SOLUTION: This amplifier uses a circuit, consisting of a microstrip line 1 formed on a substrate 4 and tapering a line width, a dielectric bridge 2 similarly tapering its width extending all over the entire side surface of this line 1 and a capacitor element terminating the bridge 2 at via holes 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-sized microwave amplifier having a wide frequency characteristic.

[0002]

2. Description of the Related Art A ladder circuit in which a series inductor and a parallel capacitor are connected in multiple stages to a microwave amplifier having a wide frequency characteristic has been used. In a microwave band where it is difficult to use a lumped element, an inductor is used as a transmission line or a spiral inductor, and a capacitor is used as an open-end stub or MIM (Metal-In).
(sullator-metal) capacitor.

[0005] FIG. 5 shows IEICE Trans. ELEC
TRON. , VOL. E78-C, Sep. 1995,
“A Wideband Monolithic Lo
ssy Match Power Amplifier
Have an LPF / HPF-Combin
ed Interstage Network "is a circuit diagram of a matching circuit of a wide band amplifier. In the figure, 30 is an active element, 31 is a transmission line, 32 is a MIM capacitor,
33 is a via hole. The transmission line 31 functions as a series inductor, the MIM capacitor 32 functions as a parallel capacitor together with a via hole 33 for grounding, and both form a matching circuit for the active element 30.

[0004]

A ladder circuit composed of an inductor and a capacitor used in a matching circuit of a broadband amplifier uses a transmission line or an open-end stub in a high frequency band where a lumped element cannot be used. It is composed of a distributed constant circuit. However, when the impedance of the active element is low or when the frequency band is wide, the required values of the inductor and the capacitor are increased, which causes a problem that the size of the distributed constant circuit is increased.

Further, when the value of the inductor is large, there is a problem that the line length of the distributed constant circuit becomes long, so that not only the size becomes large but also the characteristic becomes narrow.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to realize a microwave amplifier having a wide band characteristic by realizing an inductor and a capacitor required for a matching circuit of a wide band amplifier with a small circuit. And

[0007]

According to a first aspect of the present invention, there is provided a microwave amplifier comprising a microstrip line formed on a substrate and having a tapered line width, and a microstrip line extending over the entire side surface of the microstrip line. A circuit comprising a dielectric bridge whose width changes in a tapered shape and a capacitor element which terminates the dielectric bridge with a via hole is used.

According to a second aspect of the present invention, in the microwave amplifier, a plurality of metal patterns are arranged between two transmission lines spaced apart from each other by a predetermined distance, and a plurality of metal patterns are arranged on different sides of the adjacent metal patterns. This uses an inductance element whose ends are connected by an air bridge or a bonding wire.

A microwave amplifier according to a third aspect of the present invention uses a circuit in which a spiral inductance is formed by an air bridge or a bonding wire and a metal pattern for connection relay is provided in the middle of the spiral.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 shows a configuration diagram of a microwave amplifier according to Embodiment 1 of the present invention. In the top view of this configuration diagram, reference numeral 1 denotes a tapered line whose other end is tapered with respect to one end, 2 is a dielectric bridge, 3 is a via hole, and 8 is an active element.

In the sectional view, 4 is a substrate, 5 is a ground conductor, 6 is a dielectric, and 7 is a conductor. The dielectric bridge 2 comprises a tapered line 1, a dielectric 6, and a conductor 7,
Functions as a capacitor element. Further, the tapered line 1, the substrate 4, and the ground conductor 5 constitute a microstrip line, and function as a matching circuit for the active element 8.

Next, the operation of the microwave amplifier according to the present embodiment will be described with reference to FIG. The figure shows an inductor,
6 is a Smith chart showing how the impedance of an active element is converted into a signal source impedance by a ladder-type matching circuit of a capacitor. Since the impedance ZFET of the active element usually has a lower value than the signal source impedance Z0, it is located at, for example, a point indicated by a circle in FIG. Then, a trajectory indicated by an arrow in the drawing is drawn by a circuit composed of the inductor and the capacitor shown in the drawing, and the impedance is converted into a signal source impedance.

At the time of impedance conversion, the value of each inductor required for the matching circuit increases from the active element toward the signal source, and the value of each capacitor decreases.
Therefore, as shown in FIG. 1, on the side close to the active element, the width of the tapered line 1 and the dielectric bridge 2 is increased to increase the value of the capacitor, and the width is reduced toward the signal source side to increase the inductor. By using the matching circuit described above, impedance conversion as shown in FIG. 2 can be performed.

By arranging the dielectric bridge 2 along the tapered line 1, the circuit of FIG. 1 can be regarded as a circuit in which the ladder-type circuit of FIG. Since the bandwidth of the matching circuit increases as the number of stages of the ladder-type circuit increases, it is possible to realize a small and wide-band matching circuit compared to a case where capacitors are discretely arranged using MIM capacitors or open-ended stubs. it can.

As described above, according to the configuration of the first embodiment, a small amplifier having a wide band characteristic is configured by using an impedance transformer composed of a tapered line, a dielectric bridge, and a via hole in a matching circuit. be able to.

Embodiment 2 FIG. 3 shows a configuration of a microwave amplifier according to Embodiment 2 of the present invention.
In the figure, 12 is a strip-shaped metal pattern, 13 is an air bridge or a bonding wire, and 14 is an active element.

Next, the operation will be described. The air bridge or the bonding wire 13 can be made smaller in diameter than the transmission line, and unlike the transmission line, is arranged away from the substrate, so that the inductor component is large and the capacitor component is small. Therefore, a desired inductor can be obtained with a shorter length than the transmission line.

The metal pattern 12 functions as a relay point when connecting the air bridge or the bonding wire 13, has a function of maintaining the physical strength of the air bridge or the bonding wire, and improving the reproducibility of characteristics as an inductor. doing.

As described above, according to the second embodiment, by forming a part of the inductor of the matching circuit with an air bridge or a bonding wire, a small amplifier having a wide band characteristic can be formed.

Embodiment 3 FIG. 4 shows a configuration of a microwave amplifier according to Embodiment 3 of the present invention.
In the figure, 20 is a metal pattern, 21 is an air bridge or a bonding wire, and 22 is an active element.

Next, the operation will be described. The air bridge or bonding wire 21 can be made smaller in diameter than the transmission line and, unlike the transmission line, is arranged away from the substrate, so that the inductor component is large and the capacitor component is small. Therefore, by arranging them in a spiral shape, a desired inductor can be obtained with a smaller area than a spiral inductor formed by a transmission line.

The metal pattern 20 functions as a relay point when connecting the air bridge or the bonding wire 21 to maintain the physical strength of the air bridge or the bonding wire 21 and to improve the reproducibility of characteristics as an inductor. Have.

As described above, according to the third embodiment, by forming the inductor of the matching circuit with an air bridge or a bonding wire arranged in a spiral shape, it is possible to form a small amplifier having a wide band characteristic. it can.

[0024]

Since the present invention is configured as described above, it has the following effects.

According to the first aspect of the present invention, a microstrip line formed on a substrate and having a line width that changes in a tapered manner, and a dielectric body whose width similarly changes in a tapered shape over the entire side surface of the microstrip line. A bridge,
Since a circuit including the dielectric bridge and a capacitor element terminated with a via hole is used, there is an effect that a small amplifier having wideband characteristics can be configured.

According to the second aspect of the present invention, a plurality of metal patterns are arranged apart from each other between two transmission lines arranged at a predetermined distance, and the ends of the adjacent metal patterns on different sides are air-connected. Since an inductance element configured by connecting with a bridge or a bonding wire was used,
There is an effect that a small amplifier having broadband characteristics can be formed, and a desired inductor can be obtained with a shorter length than the transmission line.

Further, the metal pattern functions as a relay point when connecting the air bridge or the bonding wire, thereby maintaining the physical strength of the air bridge or the bonding wire and improving the reproducibility of characteristics as an inductor. effective.

According to the third aspect of the present invention, since a spiral inductance is constituted by an air bridge or a bonding wire and a circuit pattern for connecting and connecting is provided in the middle of the spiral, a wide band characteristic is obtained. There is an effect that a small amplifier can be formed, and a desired inductor can be obtained with a smaller area than a spiral inductor formed by a transmission line.

[Brief description of the drawings]

FIG. 1 is a diagram of a microwave amplifier according to a first embodiment of the present invention.

FIG. 2 is a Smith chart used for describing the operation of the first embodiment of the present invention.

FIG. 3 is a diagram of a microwave amplifier according to a second embodiment of the present invention.

FIG. 4 is a diagram of a microwave amplifier according to a third embodiment of the present invention.

FIG. 5 is a diagram illustrating a configuration example of a conventional wideband amplifier.

[Explanation of symbols]

Reference Signs List 1 tapered line, 2 dielectric bridge, 3, 33 via hole, 4 substrate, 5 ground conductor, 6 dielectric, 7 conductor, 8, 14, 22, 30 active element, 12, 20 metal pattern, 13, 21 air bridge Or bonding wires, 31 transmission lines, 32 MIM capacitors.

Claims (3)

[Claims] In a matching circuit of a microwave amplifier,
A microstrip line formed on a substrate and having a tapered line width, a dielectric bridge having a tapered width over the entire side surface of the microstrip line, and a via hole terminating the dielectric bridge. A microwave amplifier using a circuit comprising a capacitor element formed as described above. 2. A matching circuit for a microwave amplifier, comprising:
An inductance element in which a plurality of metal patterns are arranged apart from each other between two transmission lines arranged at a predetermined distance, and ends of adjacent metal patterns on different sides are connected by an air bridge or a bonding wire. A microwave amplifier, comprising: 3. A matching circuit for a microwave amplifier,
A microwave amplifier comprising a circuit in which a spiral inductance is formed by an air bridge or a bonding wire and a metal pattern for connection relay is provided in the middle of the spiral.