JPH05304419A - Frequency multiplier - Google Patents

Abstract

PURPOSE:To improve the suppression characteristic of a basic wave output by using a 1/4 wavelength coupling line as a capacitor for DC blocking of an output matching circuit. CONSTITUTION:This frequency multiplier is formed by an input matching circuit 1, an FET 2 as a frequency multiplying means, an output matching circuit 3, and a bonding wire 4 connecting the FET 2 and the circuits 1, 3. The basic wave from the FET 2 is shorted by an open stab 10, but the sufficient suppression is not enabled. However, since the gap capacitor 11 has the line of lambda/4 length, the basic wave is shorted in a gap capacitor 1. Since a double wave is strong in a coupling degree, it is outputted through the opposing line of lambda/4 length from the line of lambda/4 length within the capacitor 11. Therefore, even if the basic wave is not sufficiently suppressed, it is suppressed by the gap capacitor 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frequency multiplier, and more particularly to a frequency multiplier with improved suppression of the fundamental wave.

[0002]

2. Description of the Related Art In a conventional multiplier, a fundamental wave is suppressed by using an open stub having a length λ / 4, which is short-circuited at the fundamental wave (wavelength λ) and opened at the second harmonic as an output matching circuit. ing. A single plate capacitor is used as a DC blocking capacitor of this output matching circuit.

[0003]

In such a conventional multiplier, the input fundamental wave component is provided to the output matching circuit from the λ / 4 length open stub of the fundamental wave and the single plate capacitor so that the input fundamental wave component is not output. I'm suppressing, but I couldn't suppress it enough.

[0004]

A frequency multiplier according to the present invention comprises a multiplication means for inputting a fundamental wave signal and outputting a second harmonic wave signal, and a thin film dielectric substrate provided on the input side of the multiplication means. In the frequency multiplier comprising the strip line input matching means and the output matching means provided on the output side of the multiplying means, the output matching means is an open stub having a quarter wavelength with respect to the fundamental wave. It has a λ / 4 wavelength coupling line as a DC blocking capacitor.

[0005]

The present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a frequency multiplier according to an embodiment of the present invention. In the figure, the frequency multiplier is an input matching circuit 1,
A field effect transistor (FE) as a frequency multiplication means.
T) 2, output matching circuit 3, FET 2 and input matching circuit 1 or output matching circuit 3 are formed by bonding wires 4.

The input matching circuit 1 is provided with a strip line 6 and a single plate capacitor 7 as a DC blocking capacitor on a thin film dielectric substrate 5 to match the input fundamental frequency. The output matching circuit 3 includes a stripline 9, a λ / 4 open stub 10 of a fundamental wave, and a gap capacitor 11 having a λ / 4 long line as a DC blocking capacitor on a thin film dielectric substrate 8. Two
Matches to the harmonic frequency and suppresses the input fundamental wave. Open stub 10 and gap capacitor 11
Has a length L of λ / 4 of the fundamental wave.

The fundamental wave from the FET 2 is an open stub 1.
It is shorted with 0, but cannot be suppressed sufficiently. However, since the cap capacitor 11 has a line of λ / 4 length, the fundamental wave is short-circuited by the gap capacitor 11. On the other hand, since the second harmonic wave has a high degree of coupling, it is output from the λ / 4 length line in the gap capacitor 11 through the opposing λ / 4 length line.

FIG. 2 is a diagram showing pass frequency characteristics of one embodiment of the present invention (using a gap capacitor) shown in FIG. 1 and a conventional technique (using a single plate capacitor). From the figure, it can be seen that the suppression characteristic is improved when the gap capacitor is used as in the present invention as compared with the case where the single plate capacitor is used as the DC blocking capacitor of the output matching circuit 3 as in the prior art. For example, if the fundamental frequency is 9 GHz,
It is −0.8 dB for a single plate capacitor, but −4.0 dB for a gap capacitor.

Therefore, even if the fundamental wave is not sufficiently suppressed by the open stub, it is suppressed by the gap capacitor.

In the embodiment of the present invention, the case where the gap capacitor is used as the DC blocking capacitor of the output matching circuit has been described, but the present invention is not limited to the gap capacitor and may be a λ / 4 wavelength coupled line.

[0011]

As described above, according to the present invention, since the λ / 4 wavelength coupling line is used as the DC blocking capacitor of the output matching circuit, the fundamental wave can be sufficiently suppressed. Further, even if the position of the open stub is displaced or the characteristics of the FET are varied, the suppression characteristic of the fundamental wave can be improved.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of the present invention.

FIG. 2 is a diagram showing a pass frequency characteristic of a gap capacitor.

[Explanation of symbols]

 1 Input Matching Circuit 2 FET 3 Output Matching Circuit 4 Bonding Wire 5,8 Thin Film Dielectric Substrate 6,9 Stripline 7 Single Plate Capacitor 10 Open Stub 11 Gap Capacitor

Claims (2)

[Claims] 1. A multiplication means for inputting a fundamental wave signal and outputting a second-harmonic signal, input matching means by a strip line on a thin film dielectric substrate provided on the input side of said multiplication means, and said multiplication means. A frequency multiplier comprising output matching means provided on the output side of the output matching means, wherein the output matching means is an open stub having a quarter wavelength with respect to the fundamental wave and a λ / 4 wavelength coupling line as a DC blocking capacitor. And a frequency multiplier having: 2. The frequency multiplier according to claim 1, wherein the λ / 4 wavelength matching line is a gap capacitor.