JPS631765B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a phase modulator that combines a slot line and a coplanar line, mainly used in the microwave band.

Phase modulators using slot lines and coplanar lines are widely used because of their wideband characteristics.
However, in conventional phase modulators using slot lines and coplanar lines, two diodes connected in opposite directions to the ground are driven by a signal wave from the same terminal using a single drive circuit, so that the two diodes are connected in the forward direction. The flowing current and the voltage applied in the reverse direction cannot be set arbitrarily, and the voltage applied in the reverse direction in particular can only be set to a small value determined by the forward voltage of the diode, so when a large amplitude carrier wave passes through the diode, However, a diode that should be biased in the reverse direction is driven in the forward direction by the amplitude of the carrier wave, resulting in disadvantages such as low output saturation power and deterioration of modulation characteristics.

An object of the present invention is to propose a phase modulator in which two diodes can maintain forward and reverse biases, respectively, even when a large amplitude carrier wave is input, and which enables high-output phase modulation. It is in.

In order to achieve the present invention, instead of driving two diodes from the same terminal as in the past,
By independently driving the two diodes using two drive circuits, forward and reverse bias voltages can be set arbitrarily. Since the bias voltages can be set independently in this way, even if a large amplitude carrier wave is input, each of the two diodes can be maintained in forward and reverse bias, and good modulation characteristics can be obtained.

The present invention will be described in more detail below with reference to the drawings.

FIG. 1 shows a conventional phase modulator using a slot line and a coplanar line. In the figure, reference number 1 is a signal generator, 2 is a slot line, 3 is a coplanar line, 4 and 5 are diodes, 6 is an output plug, 7 is a capacitor that blocks signal waves, 8 is a coil that blocks carrier waves, 9 is a signal input terminal. The carrier wave supplied from the signal generator 1 is propagated in opposite phase to both conductors of the slot line, and the signal wave applied from the signal input terminal 9 causes the diodes 4 and 5 to alternately cut off and conduct the carrier wave. 0-π phase modulation is performed, and the modulated wave passes through the coplanar line 3 and is taken out from the output plug 6. The capacitor 7 prevents the signal wave from leaking to the output connector 6, and the coil 8
prevents the carrier wave from leaking to the signal input terminal 9. Since the diodes 4 and 5 are driven by a signal wave from the same terminal, a high-output phase modulator cannot be constructed.

FIG. 2 shows a phase modulator according to the invention, in which reference numeral 10 indicates a capacitance for blocking a signal wave, 11
1 is a coil for blocking a carrier wave, 12 is a signal input terminal, and the other parts are the same as in FIG. Signal waves having mutually opposite phases are applied to the signal input terminals 9 and 12,
The diodes 4 and 5 perform 0-π phase modulation by alternately blocking and conducting the carrier wave. Since the diodes 4 and 5 are driven independently of each other in this manner, a high-output phase modulator can be configured.

Although the diodes 4 and 5 are connected in the same direction as viewed from the coplanar line 3 in FIG. 2, the phase modulator can be configured even if they are connected in opposite directions.
In this case, in-phase signal waves may be supplied to the signal input terminals 9 and 12.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of a conventional phase modulator, and FIG. 2 is a circuit diagram showing an embodiment of a phase modulator according to the present invention. In the figure, 1...signal generator, 2...slot line, 3...coplanar line, 4, 5...
Diode, 6... Output plug, 7, 10... Capacitor, 8, 11... Coil, 9, 12... Signal wave input terminal.

Claims (1)

[Claims] 1 a slot line to which a carrier wave is applied to one end;
a coplanar line connected to the other end of the slot line and grounded by the slot line; and a series connection provided between both conductors at the other end of the slot line and a central strip line of the coplanar line. A phase modulator comprising a diode, a capacitor, and means for independently applying a signal to a connection point between the diode and the capacitor, and extracting the carrier wave phase-modulated by the signal from the coplanar line.