A 300 MHz SAW matched filter with reduced mismatch-loss and with a coded transducer by a low autocorrelation sidelobe sequence has been developed for 1 Mbps SS weak radiation-power wireless communication modem. This low autocorrelation sequence of 25 chips was searched out to conform DS spreading DPSK signal. The sequence reduced output signal sidelobe 6 dB lower than 31 chip m-sequence, further obtained higher processing gain than that of Barker sequences. Furthermore, to reduce mismatch-loss in temperature stable SAW matched filters, a localized layered structure has been developed. ZnO is deposited only on the normal transducer on a ST-cut quartz substrate, reducing the mismatch-loss by 9 dB. A SS radio modem unit using this SAW matched filter shows a rather long transmission distance of about 20 m with a low current consumption 210 mA, considering such a high data rate 1 Mbps and the strict power regulation.
|Number of pages||6|
|Journal||Proceedings - IEEE Ultrasonics Symposium|
|Publication status||Published - 1995|
|Event||Proceedings of the 1995 IEEE Ultrasonics Symposium. Part 1 (of 2) - Seattle, WA, USA|
Duration: 1995 Nov 7 → 1995 Nov 10