This paper proposes an improved design of a pulse-based radar. An improved design of a pulse generator is presented using step recovery diodes and a signal mixer for the received signal. Two-step recovery diodes produce pulses of 120 ps in duration. A pulse generator is improved by removing the negative power supply, resulting in a reduced number of electronic pulses. A sampling mixer at the receiver's site receives the generated signal and stretches it from picoseconds into microseconds. The improved pulse generator is also used in the sampling mixer as a strobe pulse generator, which makes the sampling mixer much simpler. The stretched signal is then sampled by a low sample rate using an analog to digital converter. The proposed radar design achieves up to 8 GHz bandwidth and an equivalent receiving sample rate of about 100 GSa/s. The radar is controlled using a software-defined radio called Red Pitaya, which is also used for data acquisition. The proposed radar design uses widely available commercial components, which makes radar design widely available with low cost implementation.
Keywords: ground penetrating radar, sampling mixer, pulse generator; pulse radar; ultra-wide-band.