Study On Reconfigurable Slot Antenna With Frequency And Pattern

Wireless systems have witnessed a fast extending demand for vast applications in our modern society.As the concretes for wireless systems,antenna modules support multiple input and multiple output(MIMO),with multi-function,anti-interference characteristics have undertaken the duty for the signal receiving and sending.However,it is of some difficulties to reveal a compact antenna modules which can fulfil multi-band or broadband requirements in different communication standards.Reconfigurable antennas,which are able to change frequencies,radiation patterns and control beam directions,is possible to solve this problem by avoiding noise sources or electronic interference,improving safety and saving resources.Therefore,such frequency reconfigurable and/or frequency reconfigurable antenna can be applied in satellite,radar and other wireless systems.The thesis is arrange as follows:A slot antenna with frequency reconfigurable coplanar waveguide feeding based on three modes loaded with PIN diodes is designed.The influence of structural parameters on the antenna performance is analyzed.The return loss and the pattern are tested and compared with the simulation results.When designing multi-frequency and reconfigurable antennas,the independent parameters method is adopted to allocate different operating frequencies due to the resonance effects of different frequencies or the coupling effect between the radiating elements.For frequency reconfigurable antennas,Mode 1 and Mode 3 tests are consistent with the simulation results,and the test results and simulation of Mode 2 loading PIN diode are different.The pattern test of the E and H planes of the three modes is consistent with the simulation.The gains of the three modes are 4.0 d B,4.0 d B,and 4.8 d B respectively,which are consistent with the simulation results.Based on loading of PIN diodes,a slot antenna with four patterns reconfigurable feeding by coplanar waveguide is designed.The effects of the main parameters of the slot antenna on the frequency and pattern under the four modes are analyzed.The effects of self-resistance and parasitic inductance on the return loss and pattern in the "on" state under DC bias are explored.The four modes maintain the consistency of operating frequency,bandwidth and gain to meet the requirements of the pattern reconfigurable antennas.The return loss of the four modes of testing is consistent with the simulation.The pattern test of Mode 1,Mode 2 and Mode 3 are in good agreement with the simulation results.Mode 4 test results are slightly different from the simulation,but the entire trend shows the largest radiation direction are the same as simulations.A single parameter to control the frequency optimization and matching of each mode method is used to design the slot antenna with reconfigurable frequency and directional pattern.The method effectively reduces the interaction between the modes.Based on the control of the PIN diode switch,each mode can be individually controlled.The problem of loading a forward bias voltage across the PIN diode during antenna testing is solved to avoid the extra new gaps.