Research And Design Of Frequency And Pattern Reconfigurable Slot Antenna

With the upcoming application of the 5th generation mobile communication technology and the emergence of various new types of communication devices,the importance of wireless communication is becoming increasingly apparent.As one of the core devices for receiving and transmitting wireless signals,antennas will directly determine the quality and efficiency of wireless communication system.On the other hand,the electromagnetic interference between various electronic devices is becoming more and more serious,and traditional antennas have been difficult to meet the design requirements in the new situation.Reconfigurable antennas have become one of research focuses,because they can realize multiple functions in one antennas aperture,thus reduce the volume of the system,and improve the electromagnetic compatibility between the loads and the antennas.This paper mainly researches on the frequency and pattern reconfigurable antennas applied to WLAN,WiMAX and WPAN and proposes three designs of reconfigurable antennas.Firstly,a frequency reconfigurable annular slot antenna is designed.By adjusting the states of the PIN diodes can change the length of slot and thus antenna can change the resonant frequencies.The simulation results show that the antenna can operate at three different working conditions in the three bands of 2.4GHz,3.5GHz and 5.8GHz respectively,and the pattern remains almost unchanged while frequency tuning.Secondly,a pattern reconfigurable patch antenna with four slots rings etched on the ground is designed.The proposed antenna is based on a rectangular patch antenna.Four slot rings with the same structure are loaded on the ground.A pair of PIN diodes are loaded in each slot,which is employed to switch main beam in five different directions for the elevation and azimuth planes.The simulation results show that common impedance bandwidth of reflection coefficient less than-10dB is from 2.39GHz to 2.44GHz.It is realized that the main-beam direction can switch from-24?to 26?for the E plane,and-22?to 20?for the H plane.The center frequency is almost unchanged in the 2.4GHz band.Finally,a frequency and pattern reconfigurable dual-semicircular slots antenna is designed.The proposed antenna consists of two semicircular slots,two T-shaped slot stubs,CPW feeder and four groups of switches.The proposed antenna is different from the conventional single-band tuning antenna,which can be reconstituted between single-band and single-band and between single-band and multi-band.The proposed antenna can operate in 2.4 GHz of single-band,5.8 GHz of single-band,and 2.4GHz and 5.8 GHz of dual-band by controlling the switches loaded in the slots.The null can switch from-18?to18?for the xoy plane in the 5.8GHz of single-band by controlling two groups of switches in the slots,and the frequency is almost unchanged.In addition,the proposed antenna is more compact with size of0.35?₀?0.30?₀,₀?is the wavelength in the free space corresponding to the 2.45GHz)than the conventional antenna,and has large bandwidth at five different working conditions.