MODULATOR, AMPLITUDE MODULATOR AND HIGH-FREQUENCY TRANSMITTING/RECEIVING APPARATUS AND RADAR APPARATUS HAVING THE AMPLITUDE MODULATOR, VEHICLE MOUNTED WITH THE RADAR APPARATUS AND SMALL BOAT MOUNTED WITH THE RADAR APPARATUS

摘要

PPROBLEM TO BE SOLVED: To provide an amplitude modulator in which an ON / OFF ratio of a prescribed value or more is obtained over a wide frequency bandwidth by controlling a forward current to a PIN diode provided in two circulators respectively. PSOLUTION: The amplitude modulator is configured in such a manner that first and second circulators each provided with a modulation section having the PIN diode are connected by using an output dielectric line 1c of the first circulator in common for an input dielectric line 1c of the second circulator and the frequency dependency of the transmission characteristic of a high frequency signal transmitting through the PIN diodes of the first and second circulators differs from each other. With the use of the two PIN diodes, even when the strength of the incident high frequency signal is changed, the change gives no effect on the frequency characteristic of the ON / OFF ratio, the frequency band at which a high ON / OFF ratio can be taken is widened, and disturbing factors on the control of the frequency characteristic of the ON / OFF ratio is reduced to surely obtain a stable characteristic. PCOPYRIGHT: (C)2005,JPO&NCIPI