JPS5991717A - Microwave circuit device - Google Patents

Abstract

PURPOSE:To attain a stable operation even at a high frequency band by providing a projecting section for grounding having a narrow part at an intermediate section to an upper face of a grounded conductor to improve the shield effect between input and output. CONSTITUTION:The narrow part 17 narrowed in the center and the projecting section 14' for grounding comprising wide sections 18a, 18b which are connected by the narrow part 17 and are wider than the part 17 ar formed integrally to the center of an upper face B of the grounded conductor 13'. Further, two source terminal 6a, 6b extended from a ceramic package 12 as a grounded electrode are connected to the wide sections 18a, 18b, and a gate terminal 5 and a drain terminal 7 are connected to micro strip lines 16a, 16b of dielectric substrate 15a, 15b provided on the upper face B at both sides of the projecting section 14' for grounding. Thus, the shield effect between the input and output is improved in this way, allowing to attain a stable operation even at a high frequency band.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a microwave circuit device such as an MIC amplifier in the microwave band using a microstrip line.

Conventional configurations and their problems In recent years, as amplifiers in the microwave band, low-noise gallium arsenide FI layers or silicon transistors are used as active elements, and MICs (MICs) using microstrip lines have been developed.
Microwave IC) circuits are common. As shown in FIGS. 1(a) and 1(b), the circuit layout of this amplifier is such that the source terminal (6) of the FET (4) is grounded, and the emitter terminal 01 of the transistor (8) is grounded.
A method of attaching matching stubs (3) (, 4) to each circuit is recommended. Note that (IJ ('11 is a DC blocking capacitor, L21 (i) is a quotient frequency choke, and (5) is a gate terminal. .

(7) is a drain terminal, (9) is a base terminal, and OI) is a collector terminal.

In such a microwave circuit, if the grounding is done halfway, the grounding will be in a floating state, resulting in a decrease in gain and unstable circuit operation. Furthermore, in the microwave band, even a small amount of lead wire causes inductance, so when mounting, it is necessary to ground the device as close as possible to the point where it should be grounded.

°C1 Current γF, mainstream microwave band FE
The package structure of A7 is as shown in Figure 2, in which a semiconductor dip is assembled into a small ceramic package A7.
It has a hermetic seal structure.

When such a semi-jpf element is used as an active amplifying element, a grounding element Q1 having protrusions (14a) and (14b) on the upper surface (B) of the order of A% is used as shown in Fig. 8 (at). The semiconductor element is mounted on the grounding body (13).

No. 81'<l (d) (As shown in el, two source particles (6a) and (6b) as ground side 1° 1 dwarf poles extending from the ceramic package 0 are connected to the protrusion of the ground conductor α3, respectively. (14a) and (14b) are connected to the top surface [F]), and the gate terminal (5) and drain connector (7) are connected to the upper surface [F] of the protruding portions (14a) and (14b). dielectric substrates (15a) (15b) disposed on
) are soldered to the microstrip lines (16a) and (16b) of the first. ing.

However, such conventional microwave circuit devices are practical up to a frequency of several GHz;
When the frequency band exceeds about 0 GIIz.

There is a drawback that the feedback capacitance between the input and output of the semiconductor element cannot be ignored, and phenomena such as one circuit going into an oscillation state or a decrease in gain occur, and the operation of one circuit becomes unstable.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a microwave circuit device that improves the shielding effect between input and output and can be expected to perform stable 7j1LI operation even at high frequencies (1).

Structure of the Invention The micro circuit of the present invention has a circuit device f+"j IJ, and a grounding protrusion having a width J to ζ81 at the middle part is provided on the upper surface of the grounding conductor.

On both sides of this grounding protrusion, a dielectric substrate having a microstrip line whose one end extends near the narrow part is provided on the upper surface of the grounding conductor, and a semiconductor is disposed on the narrow part with one end extending to the vicinity of the narrow part. The two ground side electrodes of this semiconductor element are connected to the II+14 wide part of the ground protrusions connected to each other at the narrow part, and the input and output side electrodes of the semiconductor package are respectively connected with rust. The shielding effect is reduced by connecting to the microstrip line of the electrical daughter board and connecting the two wide parts of the grounding protrusion with the narrow part to form an integrated protrusion. do.

ρ2 in the example. Hereinafter, embodiments of the present invention will be explained based on figures 4N to 6. Incidentally, those having the same function as the conventional h11 will be given the same symbol as IJ and their explanation will be omitted.

FIGS. 4(a), 4(b), and 4(c) show the grounded body 0:j-'g of the microwave circuit device i't according to the present invention.

At the center of the upper surface (13) of the grounding isobody ^, there is a narrow part Oη with a narrow middle part, and this 111, 口", 14F4r;
071 Marimo is wide and narrow part a scraps (grounding protrusion a consisting of four connected width parts (18a) and (18b)
re force (integrated and 1t).

The mounting of the semiconductor element on this ground body 69 is carried out by mounting two sources as a ground side barrier extending from the ceramic substrate θ4, as shown in Fig. gI11 children (6a) (6b) are respectively wide part (18a
) (18b), and the gate terminal (5) and drain terminal (7) are connected to the grounding protrusion 8 (ζ(rυ) on both sides of the AIJNKhs plate arranged on the two sides (I3). (15a) (15b) Microstrip line (16
a) The soldering is connected to (16b).

The effect shown in FIG. 4 will be explained in comparison with the case of the conventional example.

5th/(at is the conventional mounting state kT, , FIG. 8(
An enlarged view of el is shown. Conventionally, the top surface [F] when the ground conductor is
The protrusions B4a) and B4b) provided on the microstrip lines (16a) and (16b) are cut out to form a gap at the opposing portion of the microstrip lines (16a) and (16b), so there is no straight line between the input and output circuits. A coupling $@01 is generated and acts as a feedback capacitance between input and output. This coupling valley increases as the frequency increases.

In contrast, FIG. 5(b) is similar to FIG. 4(e) according to the present invention.
The wide portion (18aH18b) corresponding to the protruding portion (14a) (14b) is connected by the narrow portion αη, so in this case, there is a gap between the human output circuits on the ground plane side.

Coupling valleys pμ between inputs and outputs, such as the coupling valley pμ, rarely occur. In this case, a coupling valley ω)c2υ is generated between the input circuit and the narrow part αη and between the output circuit and the narrow part Qη, but this is caused by the feedback capacitance between the input and output. Because it doesn't work.

You can expect more stable operation than before.

Furthermore, in Fig. 4, a wide portion (18a) is used to reduce the coupling '8 amount Q1 that results in the feed/<tuk capacitance between the input and output.
Although (18b) is connected, the connection part is narrower than the wide part Cl8a) (18b).
+7), the gate terminal (5) and drain terminal (7) extending from the ceramic package 0 terminal are not short-circuited to the grounding protrusion (+2).

In the above embodiment, the ground conductor (1; i
Although the contact protrusion was provided along the entire width of the connector, the same applies even when the connector is shorter than one width as shown in FIG.

As described in the detailed description of the invention, the microwave circuit device a of the present invention provides the following first-order effects.

○ Feedback capacitance between input and output terminals is also affected by the packaging structure of the element used, but in the present invention, the grounding protrusion is continuous, so the input and output circuits are shielded by this, and the ground plane side The coupling valley between the input and output circuits is reduced, and when the same packaged elements are used, stable circuit operation can be expected up to a higher frequency band than in the past.

0 Since the grounding protrusion has a narrow middle portion, the input/output electrodes protruding from the semiconductor package disposed above the grounding protrusion will not short-circuit with the grounding protrusion.

[Brief explanation of the drawing]

Figures 1 (a) and (b) are general circuit diagrams of microwave band amplifiers, and Figures 2 (a), (b), and (c) are external views, perspective views, bottom views, and side views of microwave band FETs, respectively. Figures 8(a) to 8(el are external perspective views and plan views of conventional grounding conductors, A-A' sectional views in FIG. 8(b), plan views of mounted states, and A in FIG. 8(d)) -A' sectional view, Figure 4 (a) to (e)
The following are external perspective views, diagrams, and plan views of a grounding conductor according to an embodiment of the present invention; Fig. 6<a>(b) is an explanatory diagram of the operation of one conventional mounting state and the mounting state according to the present invention, respectively, and Fig. 6(a>(b))
FIG. 6 is an external perspective view and a plan view of a grounding conductor according to another embodiment. (5) ...Gate terminal, (61 (6a) (6b)
- Source terminal, (7)...Drain terminal, (6)...
・Ceramic package, aj...grounding body, 4
・・・Protrusion part for contact Jlt2, (15a) (15b)・
... Dim substance base, (16a) (16bJ... Microstrip line, 0η°°° narrow part, (18a) (
18b) - Broad Section Agent Yoshihiro Morimoto 101 Figure 1 (mu (obstacle Figure 2) (Cλ Figure 3 Figure 4 □) Figure 5 δ l Island 1/61 i'.

Claims (1)

[Claims] 1. A microstrip line with a grounding protrusion having a narrow portion in the middle on the upper surface of the grounding conductor, and one end of which extends near the narrow portion on the upper surface of the grounding conductor on both sides of the grounding protrusion. A dielectric substrate having Oi is provided, and Oi
Book l! A semiconductor element is disposed on the b+ narrow part, and two contact J′llJ side electrodes of this semiconductor element are respectively connected to the wide parts of the niI grounding protrusions that are connected to each other at the narrow part, Semiconductor device input/output 4+! ! A microwave circuit in which the + electrodes are each connected to an oil microstrip line on a dielectric substrate! M device.