Title :
Hybrid SAW-device for a European train control system
Author :
Reindl, L. ; Ostertag, T. ; Ruile, W. ; Ruppel, C.C.W. ; Lauper, A. ; Bächtiger, R. ; Ernst, H.
fDate :
Oct. 31 1994-Nov. 3 1994
Abstract :
The use of surface acoustic wave devices for a European train control system (ETCS) as a stationary transponder is shown. The Surface Acoustic Wave (SAW)-device in such a system acts as a local coherent oscillator for the balise. We show the design and analysis of the dynamically programmable SAW delay line. We use one single phase unidirectional transducer (SPUDT) for coupling the electromagnetic wave received by an antenna to the acoustic wave and vice versa. (For the test system we built a tag with 8 switchable reflectors and one additional fixed reflector as reference bit.) The switchable reflectors are designed as split finger transducers which are connected via bond wires to hybrid circuitry. This circuitry consists of capacitors and inductors for matching, and GaAs-FETs for switching. Measurements with this programmable hybrid SAW-delay line show dynamic range of 25 dB between “ON” and “OFF” reflectors with good reproducibility
Keywords :
UHF circuits; radio receivers; radio transmitters; railways; surface acoustic wave delay lines; surface acoustic wave oscillators; surface acoustic wave transducers; telecontrol; transponders; 900 MHz; European train control system; SPUDT; UHF operation; balise; dynamically programmable SAW delay line; hybrid SAW device; hybrid circuitry; local coherent oscillator; single phase unidirectional transducer; split finger transducers; stationary transponder; surface acoustic wave devices; switchable reflectors; Programmable circuits; Radio control; Rail transportation communication; Rail transportation control systems; Rail transportation electronics; Surface acoustic wave delay lines; Surface acoustic wave oscillators; Surface acoustic wave transducers; UHF radio communication; UHF receivers; UHF transmitters;
Conference_Titel :
Ultrasonics Symposium, 1994. Proceedings., 1994 IEEE
Conference_Location :
Cannes, France
Print_ISBN :
0-7803-2012-3
DOI :
10.1109/ULTSYM.1994.401575
