SAW technology for on-board processing in military satellite communications

Military satellite communications require onboard signal processing and highly directive antennas to reduce the risk of jamming. Elements of signal processing include frequency hopping over wide bandwidths, sophisticated coding, and robust modulation techniques. Surface acoustic wave (SAW) devices are ideally suited to carry out some of these onboard processing functions. The work being carried out on low and medium data rate processing for application in the Canadian extremely high frequency SATCOM program is reviewed. It is shown how SAW technology is capable of meeting many requirements for onboard processing in military communications. SAW devices are designed in the time domain and are best described as finite impulse response filters. They have applications as time delay devices, matched filters, and dispersers for frequency discrimination and block demodulation. The block demodulation capability is based on the use of a SAW chirp-Z Fourier transform (CFT), and the CFT response characteristics of SAW devices are noted. Advantages of SAW devices for onboard applications include small size, ruggedness, insensitivity to radiation, stable characteristics over a range of temperatures, and inherent reliability.