JPS60253310A - Analog frequency divider of microwave - Google Patents

Abstract

PURPOSE:To increase a frequency range which satisfies the oscillation conditions by connecting a source electrode of the 2nd dual gate FET to the 1st gate of the 1st dual gate FET to form a resistance feedback circuit and adding terminals through which the signals to be frequency divided with different phases are supplied. CONSTITUTION:A reverse-phase signal emerges at a drain electrode 12 in case a forward-phase signal emerges at the 1st gate electrode 14 of the 1st dual gate FET11. At the same time, a reverse-phase signal is also produced at a source electrode 22 of the 2nd dual a gate FET21 and then fed back to the electrode 14. Then a feedback circuit has oscillations as long as the gain of this circuit is larger than 1. The oscillation is possible up to about 6GHz with use ofa GaAs dual gate FET having its gate length set at about 1.0-0.5mum. Thus the oscillation is possible up to a range between a low frequency and 6GHz or so with use of the GaAs dual gate FET. Therefore the division is possible with this feedback circuit over an octave f=6GHz-12GHz when the mixing is carried out by means of gate terminals 16 and 25.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a microwave analog frequency divider.

[Prior art and its problems]

Microwave communication equipment, radar equipment, measurement equipment, etc. require local oscillators with good frequency stability.In particular, with the practical use of direct satellite broadcasting in recent years, the number of stabilizing oscillators of this type has rapidly increased. For this reason, research and development of stabilizing oscillators with large configurations suitable for mass production are being actively conducted in various places. Monolithic IC configurations allow mass production at low cost, but local oscillators with monolithic IC configurations are In order to stabilize the frequency, it is considered that the most suitable method is to divide the local oscillation frequency and feed back the stable frequency and the result of phase comparison to the local oscillator.To realize this method, the local oscillation A branching unit that operates at a frequency (microwave band) is required.

Conventionally, analog branch dividers have been used for this purpose, but their disadvantage is that the branch band is narrow.

FIG. 1 is a block diagram of a conventionally used analog branch divider. In the figure, 5 is a terminal into which a divided signal of frequency f is input, 1 is a mixer, 2 is a filter that passes signals of f/2 or less, 3 is an amplifier that amplifies the signal of /2, and 4 is f
6 is a feedback circuit, which is an output terminal for a frequency-divided signal of /2. With this configuration, a signal of f/2 appears in the feedback loop.

In such a conventional analog branch divider, f
/2 oscillation circuit is configured, but in order to enable oscillation, mixer 1, filter 2, amplifier 3, and feedback circuit 6 are required.
The phase delay including the phase delay must satisfy the oscillation conditions at f/2. For this reason, the frequency range that satisfies the oscillation conditions is narrow, and the fractional band is only about 20 inches at most.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the disadvantage of conventional analog dividers in that the division band is narrow, and to provide a microwave analog frequency divider with a wide band.

[Structure of the invention]

The present invention is directed to a first dual group whose source is grounded (FE).
A parallel resistance circuit is provided to the drain electrode of the T FET, and the drain electrode is connected to a second dual group (FET) whose drain electrode is grounded.
A series resistor circuit is provided, one end of which is connected to the second gate electrode of the second dual gate F]ivr in an alternating current manner, and one end of which is grounded to the source electrode of the second dual gate F]ivr. 1 dual goo) FE
connect to the first gate of T to configure a resistive feedback circuit;
This is a microwave analog branching device characterized in that the first gate of the FET is provided with a terminal for inputting divided signals having mutually different phases.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a high frequency equivalent circuit of a microwave analog frequency divider showing an embodiment of the present invention. In FIG. 2, the first dual gate (FIET) whose source electrode 13 is grounded is
The drain electrode 12 of No. 11 is provided with a parallel resistor 17, and the drain electrode 21 is connected to a second gate electrode 20 of a second dual FET 18, in which the drain electrode 21 is connected to a bridge. 2nd Dualg ~) F
The source electrode 22 of the ET 18 is provided with a resistor 23 connected in series with the other end grounded, and the source electrode 22 and the first
It is connected to the first gate electrode 14 of the dual gate FET 11 through a resistor. 16 and Go are terminals for inputting divided signals having different phases, the terminal 16 is connected to the second gate electrode 15, and the terminal 25 is connected to the first gate electrode 1.
9 is connected.

Here, if a positive phase signal appears on the first gate electrode 14 of the first dual goo FET 11, a negative phase signal appears on the drain electrode 12, and the second dual goo FET 11 receives a positive phase signal.
Similarly, an opposite phase appears at the source electrode 22 of ET 21,
This negative phase is fed back to the first gate electrode 14.

If the gain of the feedback circuit is greater than 1, the circuit will oscillate. The gate length is 1. G of OItm~0.511m
Up to about 6 GHz, if a FET is used, in a source-grounded circuit, the input #t is connected to the output side.
#? ['A signal with the opposite phase appears, and in the drain-grounded circuit, a signal almost in phase with the input appears on the output side, and the gain is about 5 dB when the source is grounded and 0 dBQ when the drain is grounded.
This allows the circuit to oscillate. For this reason, the circuit shown in Figure 2 uses a GaAa dual-gate block, and the circuit has a low frequency of ~6.
It is possible to oscillate and oscillate up to about GHz. Therefore, when mixing is performed using the gate terminals 16 and 25, this circuit performs the same operation as the conventional circuit shown in FIG. 1 over one octave from 6 GHz to 12 GHz, making frequency division possible.

The divided signals input to terminals 16 and 25 are 12G.
It is sufficient if the phase is significantly reversed up to about Hz. However, as mentioned above,
If the phase relationship is not completely reversed as in
The possible oscillation frequency of the feedback loop in the figure can be higher than 6 GHz. This means that the highest dividing frequency is 12
This means that the frequency is higher than GHz.

〔Effect of the invention〕

As described above, according to the present invention, the division ratio band is at most 2.
It is now possible to widen the branching band of a microwave analog splitter, which used to be about 0, to more than 1 octave (67% relative band), and has the effect of being widely applicable to various microwave systems such as ICs for broadcasting satellite reception. It is something.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional microwave analog divider, and FIG. 2 is a block diagram of a microwave analog divider showing an embodiment of the present invention. 11... First dual gate PET, 12... Drain electrode, 13... Source electrode, 14... First gate electrode, 15... Second gate electrode, 16... Input terminal, 17... Parallel resistance, 18... Dual gate (feed 2) FET, 19... First gate electrode, 20...
Second gate electrode, 21...Drain electrode, 22...
source electrode, 23...resistance, 24...resistance, 25.
... Input terminal patent applicant NEC Corporation Representative Patent attorney Takasumi Uchihara Figure 1 Figure 2 Figure 4 (

Claims (1)

[Claims] (1) First dual gate FET whose source is grounded
A parallel resistance circuit is provided to the drain electrode of the large-tube 2' dual-gate FET with the drain electrode connected to the drain ground.
A series resistance circuit is provided which is AC-connected to the second gate electrode of the second dual gate, and one end of which is grounded to the source electrode of the second dual gate four lamps, and the source electrode of the second dual gate n is connected to the dual generator of Ml. Connect to the first gate of the FET to configure a resistive feedback circuit, and connect to the first dual gate)
2nd gate of FET and 2nd dual gate) FE
A microwave analog branching device characterized in that the first gate of the T is provided with a terminal for inputting divided signals having mutually different phases.