Design And Analysis Of Small Dual Frequency Printed Antenna

This paper proposes an omnidirectional radiation printed antenna array that can work in two frequency bands under the IEEE 802.11a/g protocol.The antenna is composed of 2 groups of low-frequency working units and 2 groups of high-frequency working units arranged coaxially,and each working unit is composed of a binary array composed of 2 pairs of symmetrical dipole antennas placed side by side and very close to each other.All the work of this article is carried out around the above-mentioned scheme,mainly including the following contents:First,it summarizes the antenna design schemes in the field of miniaturization dual-frequency high gain at home and abroad,summarizes the antenna design ideas of domestic and foreign counterparts in the above three fields,and finally determines the research idea of this article,that is,the realization of the use of symmetrical oscillators.Omnidirectional radiation;adopts special-shaped vibrator to achieve broadband operation;adopts array form to achieve high gain.Second,the basic theory of the symmetrical dipole array antenna based on the printed form is studied,and the basic structure,radiation field form and characteristic impedance calculation involved in the important antenna unit,antenna array and feeder technology required for this study are summarized.Methods.The research content of this part provides theoretical support for the subsequent chapters.Third,modeling and simulation of CST Microwave Studio(?) software for various forms of printed symmetrical vibrator units and sub-arrays is carried out,and the reflection coefficient,horizontal plane(H-plane)pattern,gain,and pattern out-of-roundness of these models are analyzed.A detailed study was carried out and many important conclusions about the antenna structure required in this article were obtained: the size of the antenna polarization direction can be reduced by bending the vibrator;the array pattern is not circular by controlling the element spacing of the symmetrical sub-array The adjustment of the degree;the adjustment of the antenna impedance is realized by loading a special-shaped vibrator with a smooth boundary.The research content of this part provides simulation data support for the final finalization of the antenna.Fourth,an omnidirectional radiation high-gain antenna that can work in two frequency bands of WLAN is designed,and the reflection coefficient in the frequency range of 2.20 GHz?2.60 GHz and 5.13 GHz?5.43 GHz is lower than-10 d B.And the H-plane patterns in these two frequency bands are omnidirectional radiation,the maximum gain is 4.9 d Bi and 4.0 d Bi,and the out-of-roundness is 1.5d B and 3.5 d B,respectively.Fifth,the simulated antenna is made in physical objects.The test results show that the antenna can achieve a reflection coefficient of less than-10 d B in the 2.20GHz?2.60 GHz and 4.77 GHz?5.72 GHz frequency bands,and the maximum gain in the low frequency band is 5.4 d Bi,the omni-directional out-of-roundness is 1.8d B,and the maximum gain of the high-frequency band is 4.3 d Bi,and the omni-directional out-of-roundness is 3.8 d B.The antenna has the characteristics of low profile and can be used in WLAN systems.