The Research And Design Of The Microstrip Antenna Based On Complementary Double-ring Left-handed Materials

The left-handed materials (LHMs) are artificial materials where bothpermittivity and permeability are negative. Due to the opposite phase and groupvelocity of electromagnetic waves that the propagation in the LHMs, which show aseries of unusual electrical and magnetic properties. By applying Left-handedstructure to the design of microstrip antennas, performance of the antennas can beimproved greatly: extended bandwidth, higher radiation gain and better directivity.To further enhanced its gain and improve its directivity, the left-handed materialsmicrostrip antenna can be used for microstrip antenna array.This thesis is about research and design of microstrip antenna array. whichimproving the performance in microwave devices has been widely concerned. Dueto the property of conventional microstrip antenna with narrow bandwidth and lowgain, so that we select the design of a microstrip antenna with broadband andhigh-gain. Based on an ordinary patch antenna, the antenna has isolatedcomplementary double-ring and crossed strip-line gaps etched on the metal patchand ground plane，respectively. The patterned metal patch and finite ground planeform a coupled capacitive-inductive circuit of negative index metamaterial，it hasdemonstrated left-handed characteristics. The simulation result shows that thebandwidth of the novel antenna has been improved remarkably， finally， thebandwidth can be reached10.8GHz and the maximum gain is reached8.89dB. Inthe whole frequency range, the voltage standing-wave ratio is always less than1.5.The antenna has dimensions of30.6×35.3×0.8mm3. The wave propagationalong the patch induces the strongest radiation in horizontal direction instead of thevertical direction of the conventional patch antenna. Compared to the changingdielectric substrate to adjust the antenna operating frequency band antenna design in this article only adjust the width can be achieved by substantially changing theantenna band, which provides a valuable reference after adjustment of operatingfrequency microstrip antenna.To further improve the performance of the antenna, increase the gain andimprove directivity, this novel antenna is used to design the antenna array. Theantenna array consists of four antenna element composition, using the parallelfeeding, the overall size is93.4mm x74.2mm. The simulated results shows thatleft-handed materials microstrip antenna array compared to a single unit, althoughthe bandwidth is narrowed, but the gain and directivity of the antenna radiationhave been improved.the gain from8.9dB to11dB.Finally, suggestions and improvement of follow-up study have beenmentioned.