Broadband and Gain Enhanced Bowtie Antenna With Amc Ground

Abstract

A low-profile wideband bowtie antenna backed by artificial magnetic conductor (AMC) ground is presented for gain enhancement. The proposed bowtie antenna, loaded with an open stub in the upper layer, has broadband property. By using an AMC reflector, consisting of 6×9 metallic patches, the bidirectional radiation of the bowtie antenna is changed to unidirectional radiation. The distance between the bowtie antenna and the AMC surface is only λ/10 at 3.75 GHz. Both the bowtie antenna and the AMC surface are fabricated and measured. The measured results demonstrate good and stable performances, including maximum gain of 8.27 dBi, and flat gain response with variation of 0.6 dB in the wide impedance matching (S 11 < −10 dB) band from 3.05 GHz to 4.35 GHz (35.1%). Furthermore, the maximum cross-polarization level is −17 dB for both E and H planes, and the measured front-to-back ratios are more than 18 dB. Good agreement between the simulated and measured results validates the proposed design approach.

Wideband bow‐tie antenna with increased gain and directivity by using high impedance surface

“…Hence multipath interference will be minimized and smoother radiation pattern is observed in the far field. Some of the previous work carried out by several authors have maintained certain height between antenna and the high impedance ground plane to optimize impedance band width and as well as gain of the antenna . The reason for keeping some air gap between antenna and HIS is that these structures are only have the AMC properties and missing of EBG properties.…”

“…Some of the previous work carried out by several authors have maintained certain height between antenna and the high impedance ground plane to optimize impedance band width and as well as gain of the antenna. [5][6][7][8][9] The reason for keeping some air gap between antenna and HIS is that these structures are only have the AMC properties and missing of EBG properties. As in general the EBG structure helps to place the antenna horizontally on it, because it is able to produce a constructive image current in the close vicinity of horizontally placed antenna as in contrast the opposite image current developed by a PEC ground plane in the close vicinity of horizontal placed antenna.…”

“…Also practically, when these types of antennas come closure to a conductive surface their performance deteriorates in terms of bandwidth, radiation efficiency etc . So artificial magnetic conductor (AMC) has been used as the ground plane of these antennas to increase the bore sight gain and also making them low profile …”

“…Nevertheless, obtaining broadband and high gain with low profile antenna is quite a big challenge. Though low profile antennas are designed earlier, the impedance bandwidth of the antenna remains below 10%. Also in these works, there is an air space between antenna and the AMC structure with an overall height up to at least λ/10.…”

“…2,3 So artificial magnetic conductor (AMC) has been used as the ground plane of these antennas to increase the bore sight gain and also making them low profile. [4][5][6][7][8][9] Nevertheless, obtaining broadband and high gain with low profile antenna is quite a big challenge. Though low profile antennas are designed earlier, [4][5][6][7][8][9] the impedance bandwidth of the antenna remains below 10%.…”