Study On Pattern-reconfigurable Wearable Antenna

With the continuous development of wireless communication technology,communication systems have more requirements for antenna performance.Pattern-reconfigurable antennas can adjust the pattern to meet the needs according to the different application scenarios and desired modes.This paper combines the pattern-reconfigurable technology with wearable antennas to design four pattern-reconfigurable wearable antennas,and the specific work contents are as follows:（1）A miniaturized pattern-reconfigurable wearable antenna is designed.The antenna is fed by the SMA port in the center of the patch,and the PIN diode is used to control whether the short pin is connected to the patch,so that the antenna switches between TM₀₁ and TM₁₁ mode,radiating omnidirectional and unidirectional patterns,respectively.The overall size of the antenna is π×0.1632×0.012×λ_g³,which has obvious advantages in terms of miniaturization.（2）A dual-band high-gain pattern-reconfigurable antenna is designed,which can switch two modes in each frequency band,omnidirectional TM₀₁ and unidirectional TM₁₁ mode in the low frequency band,and two high-order modes of omnidirectional TM₀₂ and unidirectional TM₁₂ in the high frequency band,with gains of 4.46 and 9.52d Bi respectively.（3）A circular patch antenna with polarization-and pattern-reconfigurable is designed,using the diode to switch the TM₄₁ and TM₁₁ modes of the antenna,which can radiate omnidirectional and unidirectional patterns respectively,and in unidirectional mode,the diode can be controlled to switch the polarization direction of the antenna so that the antenna is polarized along the x-axis or y-axis.（4）A square patch antenna with wideband and pattern-reconfigurable is designed,and the diode controls whether the short pin is connected to the patch and the ground,which can stimulate the TM₀₀ and TM₁₀ modes of the rectangular patch to radiate omnidirectional and unidirectional patterns respectively.When the antenna is in omnidirectional mode,the parasitic patch and the square patch each excite a resonant frequency point,and the two frequency points are combined to form a wideband characteristic,and the relative bandwidth can reach 15.6%.The use of T-patches effectively reduces the size of the antenna.The four antennas designed in this paper have been simulated and optimized,and physical objects have been made to verify their performance,and the results in free space and on the human body prove that the antennas are suitable for wearable devices.