Research On Compact Wireless Communication Antennas Using Periodic Structure

As the "export" and "entrance" of electromagnetic wave signal in wirelesscommunications, the antennas engineering has became the one of the hot studies withhigh speed development. The customer demand for wireless terminal product lead toelectronic products emerges in endlessly in market. However customer requirementis less single, instead gradually to be the small volume, easy to carry and stabilityhigh performance. With that development tendency, people has put forward somenew requirement for terminal antenna such as small, multiple frequency, broadband,high stability and so on. Therefore, small, broadband antenna research has becomethe research hot spot in recent years.1. This chapter first analyzes the characteristic of electromagnetic bandgap(EBG) structure. EBG unit structure can equivalent to LC resonance circuit, thenone can calculate expression between the unit resonance frequency and the unit sizeby the LC resonance circuit. So this chapter puts forward dual-frequency microstripantenna with inverted "T" using EBG structure. The size of antenna is50×50mm2,through the theoretical calculation to get the working frequency band ofthe first antenna is2.4GHzand5.2GHz, which all can cover WLAN band standard.The working frequency range of the inverted "T" type dual-frequency microstripantenna is2099MHz~2944MHz and4568MHz~5409MHz, the bandwidth is800MHz above, and the gain is3.1dBi. Then the antenna is processed into a realantenna, the test result is that the working frequency range is2113MHz~2874MHzand4553MHz~5498MHz, the bandwidth is900MHz above, and the gain is2.6dBi,Simulation and test results coincide; At the same time puts forward the forkdual-frequency microstrip antenna based on the EBG structure. The size of antenna is51.5×40mm~2,through the theoretical calculation to get the working frequency band ofthe first antenna is2.4GHzand5.8GHz, which all can cover WLAN band standard.The working frequency range of the fork type dual-frequency microstrip antenna is1912MHz~2548MHz and5136MHz~6136MHz, the bandwidth is1GHz above. The two antennas using EBG structure has controlled antenna size and got a widebandwidth.2. Then presents the characteristics of complementary split-ring resonator(CSRR) structure. Based on the resonance principle, this chapter puts forwardmicrostrip antennas based on CSRR structure. In order to keep the contrast of unifiedstandard, this chapter puts forward the square, spiral and circular CSRR structuremicrostrip antennas with the same radiation patch on the top of substrate. The threeantennas has the same size of25×25mm2, the three working center frequency are5.5GHz、5.2GHz and5.5GHz respectively, bandwidth are140MHz、255MHz and190MHz respectively, gain are6.4dBi、5.8dBi and6.4dBi. Then the antenna isprocessed into a real antenna, the test result of the three antenna is that the threeworking center frequency are5.5GHz、5.2GHz and5.5GHz respectively, bandwidthare124MHz、279MHz and178MHz，the gain are6.1dBi、6.1dBi�'�5.8dBi. In theend, the paper has sum up a comparative analysis on the size parameters to influencethe performance of microstrip antenna. The three antennas using CSRR structure asmetal ground make antenna size decreases, and at the same time gain bigger, goodperformance.The simulation and measurement result of designed antennas of this thesis havea match; the results showed that the designed antennas can well to meet the needs ofthe wireless communication system.