Design Of E-Shaped Broadband Antenna And Duplexer For WLAN

In recent years,as communication systems become more complicated,the demand for antennas is increasing day by day,as spectrum resources become more and more intense,it is necessary to make a broadband antenna that can cover many systems.The duplexer is mainly used for the RF front,it's a special bidirectional three-port filter.Its role is:on one hand,the signal received from the antenna is sent to the system,on the other hand,the signal from the power amplifier is fed to the antenna.It can ensure the sending and receiving are simultaneously.The microstrip duplexer is easy to connect with other PCB plates.It has the characteristics of small volume,easy processing and low cost and so on.Coaxial cavity duplexer has the advantages of high Q value,low insertion loss,large power capacity,easy implementation and stable performance and so on.Therefore,in this thesis,a microstrip duplexer of WLAN and a cavity duplexer of WLAN are designed for comparison.An E-layer wide frequency antenna for the base station?bluetooth?wireless local area network and other occasions is designed in this thesis.The antenna consists of two dielectric plates.The main radiation patch adopts an E-shaped patch,the parasitic patch adopts a patch with a U-shaped gap to generate multi-point resonance.The antenna is fed using a coaxial line and a metal washer is added to the coaxial probe to adjust the match.The designed broadband antenna has a return loss of more than 12dB in 1.82GHz-2.66 GHz band,a maximum gain of 8.12 dBi at the center frequency and a relative bandwidth of 37.3%.A microstrip duplexer for WLAN band is designed in this thesis.The downlink frequency band works at 2.45GHz(2.40-2.484GHz),and the upstream band works at the 5.8GHz band(5.725-5.85GHz).Two bandpass filters are selected the structure of one-fourth open-circuit branch line with SIR double mode resonator.Zero point is introduced between the upstream and downstream bands.In the downlink frequency adding the "spurs" structure to improve the external inhibition.Using ADS and HFSS software to simulate duplexer,and process testing,the isolation is more than 40dB,the frequency of the two passband is slightly offset,the insertion loss variation,will continue to optimize the analysis of microstrip duplexer.A coaxial cavity duplexer for WLAN band is designed in this thesis.The downlink frequency band works at 2.45GHz(2.4-2.5GHz),and the upstream band works at the 5.8GHz band(5.725-5.85GHz).The coaxial cavity duplexer is designed with the structure of coaxial cavity.The 2.45GHz band is 4 cavity,and the 6 cavity is used in the 5.8GHz band.The coaxial cavity duplexer adopts the software Coupilfa?ADS?Ansoft Designer,and HFSS to co-simulation.After meeting the design requirements,drawing the processing drawings in CAD for processing and testing,the insertion loss is less than 2.9dB of two passbands,the echo loss is greater than 20dB,and the isolation degree is more than 40dB.