JPH03192801A - Monolithic microwave integrated circuit device - Google Patents

Abstract

PURPOSE:To improve the effect of preventing reflection of a microwave in a bias circuit and to prevent the oscillation by forming a resistor made of a conductive layer on a board as a bias circuit, connecting an open stub made of a microstrip line forming a small capacitance to one end of the resistor and connecting a parallel plate type capacitor to the other end. CONSTITUTION:The bias circuit 6 consists of an open stub 19 comprising a microstrip line connecting to one terminal of a resistor 9 and a parallel flat plate type capacitor 10 connecting to the other terminal of the resistor 9. Since the capacitance of the small capacitor connecting to one terminal of the resistor 9 is very accurately set by an open stub 19, a filter circuit comprising the small capacitance capacitor set by the said open stub 19, the resistor 10 and the capacitor 10 is formed to provide a desired characteristic. Thus, the power reflecting coefficient at the operating frequency band when viewing the bias circuit 6 from a connecting terminal 13 is designed to be very close to the unity and the leakage of a microwave is prevented.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a monolithic microwave integrated circuit (hereinafter abbreviated as MMIC) that operates in an ultra-high frequency band on UHFHF. Especially improved colander.

(Prior Art) Figure 3 shows a circuit diagram of a commonly used MMIC, and (1) shows an active circuit formed in the MMIC, such as a GaAS field effect transistor (hereinafter referred to as FET). Its source is grounded, its train is connected to the output terminal (2), and its gate is connected to the gate input terminal (4) through a matching circuit (3). The gate input terminal (4) also passes through a matching circuit (5) to a bias circuit (6) for applying a bias voltage to the gate of the FET (H).
)It is connected to the. The bias circuit (6) consists of a small capacitor (8), a resistor (9), and a relatively large capacitor (10).
), resistor (9), and capacitor (10) prevent the microwave signal from leaking to the bias power supply terminal (11),
It also acts as a filter circuit to prevent leaked microwaves from being reflected and oscillated.

FIG. 4 shows a plan view of a pattern when the bias circuit (6) of FIG. 3 is realized with a weight C. In FIG. 4, parts that are equivalent or corresponding to those in FIG. 3 are given the same reference numerals. In FIG. 4, parallel plate capacitors (8) and (10) are connected to both ends of a resistor (9) made of a conductive layer formed on a semi-insulating GaAs substrate (not shown). A small capacity parallel plate capacitor (8) consists of a base electrode (81), an insulating film (82), and an L base electrode (83), and the base electrode (81) is connected to the matching circuit (5) and a resistor in FIG. (9
), and the upper electrode (83) is grounded. Similarly, a parallel plate capacitor (In) with a relatively large capacity also has a base electrode (91) and an insulating film (
92), and an upper electrode (93);
91) is connected to a conductive layer forming a bias power supply terminal (11) and a resistor (9), and an upper electrode (93) is grounded.

(Invention or problem to be solved) In the conventional MMIG as described above, the bias circuit (6)
Since the small capacity capacitor (8) constituting the filtering circuit is also configured as a parallel plate capacitor like the relatively large capacity capacitor (lO), the electrodes constituting the capacitor (8) of this scheme-1 Alternatively, the peripheral effect of the insulating film appears strongly, and even if the dimensions of each electrode (81), (83), the thickness of the insulating film (82), etc. are adjusted accurately, the capacitance ta value does not reach the desired value. It is difficult to set up. If the desired capacitance value cannot be obtained for the capacitor (8), microwaves may leak and a reflected wave may be generated by the bias circuit (6), which may also cause undesired oscillation. Yes, for this reason, it is possible to reduce the reflection and noise of the IC.
There were problems such as difficulty in increasing the gain.

This invention particularly improves the viscosity of a small capacity capacitor (8) to prevent oscillation in the bias circuit (6).
, improve the power of microwave blocking, bias circuit (6
) to create a low-noise, high-gain MMC with low reflections.

(Means for Solving the Problems) The MMIC according to the present invention has a resistor made of a conductive layer formed on a substrate 1- as a bias circuit for supplying a bias voltage to an active circuit, and a resistor connected to one end of the resistor with a small capacitance. A circuit is used consisting of an oven stub consisting of a microstrip line acting as a capacitor and a parallel plate capacitor connected to the other end of the resistor.

(Function) According to the present invention, since a stub made of a microstrip line is used as a small capacitance capacitor, its capacitance value can be set accurately, and the bias circuit (
The oscillation prevention ability and microwave blocking ability in 6) are improved.

(Embodiment) Fig. 1 shows an equal number circuit of mass C according to the present invention, and the second
The diagram shows the bias circuit (6) used in the MMIG in Figure 1.
Among the elements in FIGS. 1 and 2, which show plan views of the patterns, the same elements as those in the conventional MMIG of FIGS.

In other words, (1) is an active circuit section such as GaAs.
The source of the FET is grounded, the train is connected to the output terminal (2), and the gate is connected to the gate input terminal (4) via a matching circuit (3). Gate input terminal (
4) is also connected to a bias circuit (6) for applying a bias '1 [pressure] to the gate of FET (1) via a matching circuit (5).
)It is connected to the. The bias circuit (6) includes, for example, a resistor (9) made of a conductive layer formed on a semi-insulating GaAs substrate (not shown), and an oven staff made of a microstrip line connected to one end of the resistor (9). (19
), and a parallel plate capacitor (10) connected to the other end of the resistor (9). The oven star (19) acts as a small capacitor, and its capacitance value can be accurately determined by the impedance value of the microstrip line constituting the oven star j (+9) and its electrical length. The non-oven side connecting end (13) of the oven stub (19) is connected to the matching circuit (5). On the other hand, the parallel plate capacitor (10) has a base '+jj, a pole (91), and an insulating film (92).
, and a top electrode (93), which includes a bottom electrode (91).
is connected to the bias power supply terminal (+1), and hJ′l! The electrode (93) is grounded.

In the MMIG of the present invention, the capacitance value of the small capacitor connected to one end of the resistor (9) can be set extremely accurately using the oven stuff (19). ), a resistor (9), and a capacitor (10) can be configured to exhibit desired characteristics. Therefore, the power reflection coefficient in the operating frequency band when looking from the connection end (13) to the bias circuit (6) side can be designed to have a value extremely close to 1.
It is possible to effectively prevent microwave leakage and oscillation.

In addition, in the embodiment described above, the bias circuit (6) for applying a bias voltage to the gate of the FET (1) is explained, or it is used for applying a train voltage or for an active circuit of MMIG including a tie-out. It can also be used as a bias circuit for supplying a bias voltage. Although the above embodiments are examples using Ga8 substrates, it goes without saying that they can also be applied to devices using other ■-V group, II-Vl group compound semiconductor substrates, and Si substrates. do not have.

〔Effect of the invention〕

As described above, in the MMIG of the present invention, a resistor (9) made of a conductive layer is formed on the substrate 42 as a bias circuit (6), and a microstrip line forming a small capacitance capacitor is formed at one end of the resistor (9). Since we are using a capacitor constructed by connecting an open capacitor and a parallel plate type capacitor to the other end, it is especially important to set the capacitance value of the L capacitor accurately. It is possible to prevent 1F oscillation and improve the 1F effect of preventing microwave reflection in the bias circuit, making it possible to realize a low-noise, high-gain MMI (:).

[Brief explanation of drawings]

FIG. 1 is a diagram showing an equivalent circuit of the L main part of an embodiment of the monolithic microwave integrated circuit of the present invention, and FIG.
A plan view of an example of a bias circuit used in an embodiment of the monolithic microwave integrated circuit of the present invention shown in FIG.
Figure 3 shows a conventional monolithic microwave integrated circuit.
・A diagram showing an equivalent circuit of the main part of the example. FIG. 4 is a plan view of a bias circuit used in the conventional monolithic microwave integrated circuit shown in FIG. (1)...FF, T (emotional circuit), (6)...
...Bias circuit, (9)...Resistance, (lO)...
・・Parallel plate capacitor, (19)・・Oven stud made of microstrip line, (91)・・・
...First metal film, (92)...Insulating film, (9
3)...Second metal film. Il'jl Tsuyo Osamu Hitoshi Masuo

Claims (1)

[Claims] (1) Comprising an active circuit formed on a substrate and a bias circuit supplying a bias voltage to the active circuit, the bias circuit includes a resistor made of a conductive layer formed on the substrate, and a resistor of the resistor. an open stub made of a microstrip line connected to one end and acting as a small capacitance capacitor; a first metal film connected to the other end of the resistor and formed on the substrate; and a second metal film formed through an insulating film.