Study on Array Antenna and Wideband Antenna
|School||Xi'an University of Electronic Science and Technology|
|Course||Electromagnetic Field and Microwave Technology|
|Keywords||UWB multi-band εDEAG beam-shaping|
With the rapid developments of wireless communication and mobilecommunication technologies, there is a growing requirement for antennas with betterperformance. Meanwhile, the researches of wideband compact planar antennas arebecoming more and more important. Among all these antennas, the ultra-wide band(UWB) antennas and wideband multi-band antennas are the hot spots of antennadesigns. Moreover, as the key point of the design of antenna arrays, the beam-shapingand optimization technologies for array pattern synthesis are urgently demanded. Thisthesis mainly focuses on the research and design of wide-band antennas and thebeam-shaping and optimization technologies of antenna arrays for communicationsystems. The author’s major contributions are summarized as following:A dual band-notched planar ultra-wideband monopole antenna using hybridresonators is presented. The proposed antenna is composed of a regular octagonradiation patch and a defected ground plane. By etching a complementary electric-LC(CELC) resonator on the ground plane and a split ring resonator (SRR) on the radiationpatch, the hybrid resonators are obtained and thus dual band-notched characteristics areachieved. Experimental results demonstrate that the proposed antenna operates over aUWB frequency range from2.9to12.4GHz for VSWR <2, while providing dualband-stop function in the frequency bands of3.3to3.6GHz and5.2to5.8GHz, whichshows that the antenna can be applied to UWB applications.A compact tri-band claw-shaped monopole antenna for WLAN/WiMAXapplications has been designed, fabricated, and measured. The antenna is composed of anovel claw-shaped radiation patch and a modified rectangular ground plane. The threearms of the radiation patch generate three desired resonate frequencies around2.5,3.5and5.5GHz respectively. Moreover the three arms exhibit a relatively independencewhile being tuned separately which is convenient for the antenna design. Good radiationcharacteristics and stable antenna gains for the operating bands have been obtained,which shows the antenna is suitable for multiband wireless applications.The ε constrained differential evolution algorithm with Gradient-based mutation（DEAG）, which is realized by applying the ε constrained method and the repairoperation (Gradient-based mutation) into DE, is presented. The algorithm has betterperformance on solving difficult constrained optimization problems such as thebeam-shaping and optimization for base station array pattern synthesis. On this basis, a program for beam-shaping and optimization of antenna arrays, which is based on theDEAG, is proposed. The key procedures of the program design are presented. A basestation antenna linear array with eight elements is used for testing the program. Thecalculation and experimental results show good agreement which proved that theprogram can be used for beaming shaping and optimization.