Study On Wideband Filtering Slotline Antennas

With the continuous developments of wireless communication systems,various of novel electronic devices(i.e.,notebook personal computers,mobile phone,PAD,and etc.)are evolving to be low power-consuming,multi-functional,compact-size and integratable.This trend makes the design of compact antennas more and more challenging.Therefore,it is of great practical significance to develop a wideband filtering antenna with excellent performance.In this thesis,the slim slotline antenna is chosen as the initial prototype.Firstly,a wideband antenna is studied by exciting and disturbing multiple radiation modes.Then,offset feed technique is employed to excite the even-order resonant mode and to introduce the gain notch characteristic.Finally,the design approach of wideband filtering antenna within slotline radiator is derived.The correctness,reliability and effectiveness of the design method are both numerically and experimentally verified.The contents of this thesis are organized as follows:1.The inherent E-field distributions and the associated radiation behaviors of a basic slot antenna are analyzed at first.Then,two more short-circuited branches are introduced to form a triple-digit,fork-like feed network.Next,a pair of bilateral slotline stubs is loaded symmetrically near the E-field nulls of the third odd-order mode along the center slotline.The major parameters of the proposed antenna are studied by simulation.Finally,the design method of the wideband antenna with multiple radiation modes is derived.2.A novel non-travelling-wave,triple-mode wideband slot antenna is designed.The major parameters are studied by IE3 D,then antenna prototypes are fabricated and measured to validate the design approach.Finally,the measured results are agree well with the simulated ones.The proposed antenna's radiation bandwidth has a wide bandwidth over a range of 3.29 to 4.60 GHz with a stable radiation pattern.The relative bandwidth has reached 33.2% and the average peak gain is 5.8 dBi.3.Based on the wideband design approach,the filtering antenna design method is studied.The eccentric feeding is employed to partly excited the even-order modes,a gain-notch character in the broadside is gained resultly.The major parameters are studied by IE3 D.The impedance bandwidth filter antenna is ranged from 2.66 GHz to 4.66 GHz,and the gain is decreased within the bandwidth.