Uwb Pulse Source And Stop Band Antenna Design

A time-domain pulse generator based on15classes avalanche transistors connected by MARX circuit and two UWB antennas with multiband rejection characteristics based on new-style Split Resonator Ring (SRR) Defected Ground Structure (DGS) are presented respectively in the work, both of which can realize the engineering application in ultra-wideband transient electromagnetic pulse system.In the chapter of pulse source, first of all, several typical methods of pulse generating are described, and several mainstream solid-state switching devices are selected as the core devices of pulsed source. Secondly, several major solid-state switching devices and their corresponding typical pulse forming circuits are analyzed respectively. Thirdly, based on requirements of radar system, which include high-peak amplitude and narrow pulse width of the output pulse, one kind of avalanche transistor whose model is FMMT415is selected as the key switching device of the designed pulse generator. Lastly, demonstration of indicators, calculation of circuit parameters, selections of devices and PSPICE simulation of the circuit are conducted respectively before manufacture, testing and optimization. The experiment results show that the pulser can generate zero-order Gaussian pulse with Full Width at Half Maximum (FWHM) of275ps, continuous adjustable repetition frequency within5kHz and peak amplitude of1.044kV at50Ω load. There are two main innovations in the design of pulse source, the first of which is quasi-gradual declining of last six discharge capacitors aiming to the waveform optimizing, and the values of the last six capacitor are47pF,47pF,47pF,15pF,15pF and10pF respectively; The second of which is the use of the shunting capacitor (1.5pF) parallel connected to terminal load, and a low-pass filter is formed by this capacitor along with parasitic inductance of the circuit, as a result, the output waveform has been further optimized, so this innovation is named as equivalent filtering of shunting capacitor method. Owing to above innovations, the designed pulse generator could meet the engineering requirements of ultra-wideband pulse source applied in ground penetrating radar system.In the chapter of UWB antenna, a Coplanar Waveguid (CPW) fed UWB monopole antenna with matching steps and semi-elliptical radiating patch is designed, which has good impedance bandwidth of2.9-17.8GHz for VSWR less than2. Due to mutual conflict interfere between narrowband communication systems and UWB system, two kinds of multiband rejection antenna is proposed based on the UWB antenna designed above, the first multiband rejection antenna based on the semi-circular SRR DGS could realize three frequency stop-bands of3.8-4.3GHz (C-Band),5.17-5.9GHz(WLAN) and7.8-8.3GHz(X-Band), and the main innovation of the triple band-notched antenna is the using of a single structure which could realize three stop bands; And the second multiband rejection antenna based on rectangle SRR DGS can realize four frequency stop-bands of3.8-4.3GHz (C-Band),5-5.35GHz(lower WLAN),5.65-6.05GHz (upper WLAN) and7.8-8.4GHz(X-Band), and the main innovation of this quadruple band-stop antenna is the using of the rectangle SRR, the consistent split direction of which could realize four stop bands.