High Power Subnanosecond Generator For UWB Radar
Subnanosecond pulse generator is one of the most important elements of ultra-wideband (UWB) radar. Parameters of impulse generator influence to radar performance since it depends on radiation power and receiver sensitivity. There are some ways to get high performance factor of the UWB radar. It can be achieved as increasing of radiation power as multiply sampling data accumulation. In this paper we shall describe solid state, high power subnanosecond generator for portable UWB radar design.
There are two methods to reach high value of UWB radar performance factor (PF) that we understand as ratio of peak radiation power to receiver sensitivity. Usually PF increasing is achieved by additional signal processing and post-processing of acquiring data. Radiation power increasing is more attractive method since lead to linear rise of PF value. However it is difficult way because range of commercial available nanosecond and subnanosecond pulse generators are hardly limited especially for application in portable UWB radar. It should be simultaneously satisfied some conditions: high peak power and pulse repetition rate (PRR). compact size, time stability and long lifetime, high efficiency and reliability.
Theory of The Generator Operation
It is known a lot of components that is successfully used for nanosecond pulse generation (Meixier L.. 1991: Litton A.B. et al.. 1995: Agee F.J. et al.. 199S). However everyone has some disadvantages. For example step recovery diodes (SRD) are stable and reliable, form impulse with as small duration as 100 picoseconds but only some dozens volts in magnitude. Krytron or hydrogen thyratrons conversely generate extremely