Analysis And Design Of Low-Profile Miniaturized Communication Antenna

With the rapid development of mobile communication and the continuous improvement of integration degree in recent years,the application demand of small-size,multi-band and broadband antenna is increasing day by day.As the core component of communication transmission system,the performance of antenna directly affects the quality of transmission signal.Wireless communication equipment is developing towards multi-function and miniaturization.Therefore,it is of great practical significance to design wide-band and small-size antennas in compact space.In this paper,the antennas used in wireless communication system are studied in detail,including planar inverted F antenna and fractal microstrip antenna.The main work of this paper is as follows:1.Two PIFA antennas based on short-circuit loading technology are designed.Firstly,a planar inverted F antenna loaded with U-shaped slot is designed.The size of the antenna radiation patch is 30 mm×15 mm.Simulation results show that the antenna has a maximum gain of 4.9 dBi in the 2.37 GHz-2.39 GHz(TDD-LET)band.Compared to the microstrip antenna operating at the same frequency,the patch size is reduced by 76.5%.Then,an ultrawideband PIFA antenna loaded with short-circuit pins is designed to improve the bandwidth by introducing a folded inclined plane feed.Simulation results show that the antenna operates in 3.98 GHz-10.34 GHz band.It has a relative bandwidth of 88.6% and a maximum gain of 7.5 dBi.The antenna size is 18 mm×15 mm×7 mm.2.A dual-frequency folded PIFA antenna is designed.A MIMO antenna with high isolation and horizontal omnidirectional radiation characteristics is designed based on the antenna.The dual-frequency folded PIFA antenna is based on the traditional PIFA antenna structure.The wide edge of the radiation patch is bent down 90° to achieve miniaturization.The antenna has a size of 34 mm×27 mm×10 mm and operates in 1.735 GHz-1.88 GHz and 3.3GHz-3.6 GHz.Based on the dual-frequency folded PIFA antenna,a four-port MIMO antenna is constructed.Simulation results show that the minimum isolation of MIMO antenna is 16 dB in low frequency band and 20 dB in high frequency band without using decoupling structure.By controlling the phase of the feed signal,the MIMO antenna has a horizontal plane circularity of(-3 dB,3 dB)and good horizontal omnidirectional radiation characteristics.3.A fractal microstrip antenna is developed.The patch of the microstrip antenna is cut and rearranged by Giuseppe Peano fractal technology to realize the miniaturization of the antenna.The radiation patch size of the antenna is 17 mm×17 mm,which is reduced by 42.2%compared with the normal microstrip antenna.The measured results show that the gain of the antenna is greater than 1.2 dBi in 3.39 GHz-3.59 GHz band.