Research On Ultra-wideband Antenna And Its Loading Technology

With the wide application of high-power pulses in plasma physics,high-power microwaves,and bioelectromagnetism,research on high-power pulse sources is becoming more and more important.As a new type of solid-state switch,the Photoconductive Semiconductor Switch(PCSS)has the advantages of fast conduction speed,large power capacity,high repetition frequency,simple structure and small size.The switch made of GaAs material in the photoconductive switch is widely used at present,and it can withstand a large bias voltage.GaAs materials exist in both linear and nonlinear modes of operation,with different properties in both modes.The PCSS combined with the Blumlein line can be applied to high voltage pulses,or the design of ultra-wideband signal sources,used as high power sources for ultra-wideband radars,electronic warfare,and high voltage pulse sources for bioelectromagnetics and civil applications.The content of this paper is about the Blumlein line based on the PCSS.The PCSS adopts the structure of GaAs material and the opposite surface electrode.The gap between the two electrodes is 3mm,and the DC charging voltage which can be adjustable is up to 12 kV.Then,the optical pulse generating circuit required for the PCSS is designed,that is the driving circuit of the laser diode.The MOS tube of the type IPD78CN10 NG is used to generate the pulse current required by the laser diode,and the current which control its output power can be changed through different drain voltages.Next,the author designed the corresponding Blumlein line based on the PCSS used.Firstly,the basic principle is explained,and then the calculation formula of the load output pulse value of the Blumlein line of any series is derived by theory.Then,the software of Pspice and CST are used to simulate and analyze the output pulse from the perspective of road and field respectively.The various influencing factors are designed and tested for single-stage Blumlein lines.In the case of charging voltage is 9.75 kV,the voltage of the output pulse can achieve 8.31 kV.On the basis of single stage,the superposition method of multi-level Blumlein lines is discussed,and the advantages and disadvantages of each method are discussed.Then a new superposition method is proposed and the structure from two levels to five levels is designed.In the latter experiment,the two-stage Blumlein line was processed and tested to achieve a 72.7% pulse output with a pulse width of 1.52 ns,slightly larger than the expected target.