Cavity backed embedded antenna on cylindrical surface for conformal applications

Abstract

The use of planar antenna for conformal applications is of great engineering use, however antenna embedding into conformal shapes need to be carefully studied. The analysis of cavity-backed proximity coupled micros trip antenna embedded in a cylindrical surface is presented. Cavity backed antenna is used for higher bandwidth. A dielectric layer, which is integrated on the surface of the antenna, is designed to shield the patches and make the cylindrical surface continuous. Dielectric substrate Rogers RT/duroid® 5880 with Er =2.2 and metallic material Aluminum is used for the cylinder. Edge fed and coax fed configurations are compared. Based on the ease of manufacturing and testing, coax fed antenna is used for embedding for conformal application. Simulation results including S-parameters, radiation pattern and gain are provided. The parametric study including the effect of material, thickness, radius and dielectric cover is also discussed for the design. Two types of cylindrical cuts are used with radii of 2A, 51.. and 101.. and thickness of 0.508mm and 7mm. The results indicate that the bandwidth of edge-fed and coax-fed antenna exceeds 40% and 30 % respectively at X-band and the impedance of the antenna is not sensitive to the cylindrical radius, however the radiation pattern is affected if the cylinder is cut into half or reduced even further. The radiation pattern is more stable in the case of dielectric half cylinder with reduced thickness as compared to the metallic reduced cylinder with increased thickness. The effect of dielectric cover is to shift the frequency band towards lower frequencies. Higher gain is observed for metallic cylinders. Such an antenna can easily be used for platform mounted applications like VA V, Missile or satellites.

Comparative study of antenna embedded in singly and doubly curved dielectric surfaces

“…The study does not include the effect of dielectric cover as it has been shown in [13]- [18] that its effect is to shift the frequency towards lower end and slight increase in gain but no significant effect on the radiation performance of the antenna.…”

“…This paper is an extension of [13] and [14] to study the comparative results and obtain some design guidelines for the design of conformal embedded antenna applications. The study is restricted to the dielectric structures only.…”

“…The study is restricted to the dielectric structures only. In this paper, the antenna mentioned in [13] and [14] is used for comparative study for embedding in singly and doubly curved surfaces to obtain broadband performance. The antenna has 34 % (7.78 -10.98 GHz) bandwidth with coaxial probe feed.…”

The wideband microstrip antenna with capacitive feed with the low level of the VSWR

“…As a result, the operating frequency band of these antennas is small and, basically, does not exceed a few percent. There are microstrip antennas, whose operating frequency band by level of the VSWR ≤ 2 is 10 % or more [1][2][3][4][5]. However, by level of the VSWR ≤ 1.2 (|S(1,1)| ≤ −20 dB) their operating frequency band is usually less than 10 %.…”