| 摘要 |
PROBLEM TO BE SOLVED: To provide the transponder circuit of high gain at the time of transmission provided with wide angle standby characteristics in a small size at a low cost. SOLUTION: The transmission/reception circuit 16 for up link of a transponder 12 is constituted by using a modulator 24 provided with reversible characteristics. Non-modulated signals received by an element antenna 26 are modulated by the reversible characteristic modulator 24 and re-radiated from the element antenna 28 and the non-modulated signals received by the element antenna 28 are modulated by the reversible characteristic modulator 24 and re-radiated from the element antenna 26 inversely. Since the signals re-radiated from the element antennas 26 and 28 are in the relation of common-mode synthesis relating to the arrival direction of the non-modulated signals, directivity is narrowed and the gain becomes higher relating to transmission. For the reception of the non-modulated signals, the standby characteristics of a wide angle provided individually by the respective element antennas 26 and 28 are realized. |
