A low power Pulse Frequency Modulated UWB radar transmitter concept based on switched injection locked harmonic sampling

Pulse Frequency Modulated ultra-wideband (PFM-UWB) radar signals have been introduced as a very capable option for UWB ranging and wireless local positioning. PFM-UWB signals allow for simple correlating receivers and for a very efficient use of the UWB spectral mask. The generation of pulse frequency modulated (PFM) ultra-wideband (UWB) signals usually requires a fast tunable RF-VCO and good linear RF amplifiers. The resulting complexity and power consumption of a PFM-UWB transmitter can be considered as a drawback compared e.g. to simple impulse radio UWB systems. In this paper, a PFM UWB transmitter concept is introduced that overcomes these drawbacks. The novel approach is based on harmonic sampling with a switched injection locked oscillator (SILO). RF signal generation is solely based on a very simple fixed frequency pulsed LO that samples the phase of an injected harmonic of a baseband FM signal. In this paper the basic concept for switched injection locked harmonic sampling PFM UWB signal generation is introduced and its feasibility is proved through measurements with a 7-8 GHz PFM UWB transmitter prototype.