| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a radar antenna, for example, for an underground radar with the wide frequency band of a gain by changing the center frequency of the gain of a transmitting antenna and that of the gain of a receiving antenna within a limit where each frequency band is overlapped. SOLUTION: In transmitting and receiving antennas, a standing wave with a half wavelength corresponding to each antenna gain is formed. Therefore, in the transmitting antenna with a larger dimension in the longitudinal direction where the standing wave is formed, a center frequency ft of a gain Gt is lower than a center frequency fr of a gain Gr of the receiving antenna with a smaller dimension in the longitudinal direction where the standing wave is formed. A 3 db reduction bandwidth fw of a transmitting and receiving foldback total gain is wider than the 3 db reduction bandwidth of the antenna gain Gt of the transmitting antenna or the 3 db reduction bandwidth of the antenna gain Gr of the receiving antenna, thus increasing the bandwidth of the gain and greatly improving the performance of, for example, an underground radar that requires a high spatial resolution for a proximity range.</p> |
