Substrate‐insensitive microstrip monopolar antenna

Abstract

A substrate-insensitive microstrip monopolar antenna is proposed and analyzed. The measured operational bandwidth of this antenna is 12% and this antenna has typical monopolar omnidirectional radiation patterns in the operational band. By using the hollow configuration, the efficiency and maximum gain of this antenna change little with the loss tangent of used substrates and can respectively reach 95% and 8.1 dBi when all used substrates are FR4. The proposed configuration provides a possibility to make antenna performance free from the long-lasting dependence on substrate's quality.

Efficiency enhancement techniques of microwave and millimeter‐wave antennas for 5G communication: A survey

“…Substrate insensitive hollow antenna is presented in paper 14 . In contrast to full substrate antennas, the characteristics of a hollow antenna are not reliant on the loss tangent of the antenna.…”

“…Because they are insensitive to varying permittivity and loss tangent values, they are appropriate for usage on a variety of board substrates. It may be used in a wide range of applications, including microwave and mm‐wave 5G applications, low‐cost IoT antennas, biological sensors, and many more 14 …”

“…In the broadside direction, the gain of a patch antenna utilizing an HLE slab is boosted by 7 dB. Aperture efficiency (ep) can be found using the following formula (14) for microstrip patch antenna with HLE slab. 73 Aperture efficiency…”

“…Low loss, low permittivity dielectric substrates can be used to reduce dielectric losses and power dissipation losses in substrates, however they are expensive and increase the size of the antenna owing to an increase in the value of the guided wavelength. 1,2,8,9 Dielectric losses or substrate losses can be reduced using several other ways such as removing a section of the substrate, 8 constructing an air gap, 10 air filled metallic cavity, 11 substrate insensitive antennas, [12][13][14] Fabry-Perot antennas, [15][16][17] and employing artificial materials in substrate. 18 Conductor losses or ohmic losses can be decreased by employing several stacked laminated conductors for patch instead of a single conductor, [19][20][21] dielectric material for patch instead of metallic patches, 22 dense dielectric patch, 23 and so on.…”

“…36,37 Mutual coupling increases as a result of surface wave and cross-polarized radiation from individual antennas, which reduces radiation efficiency. 38,39 Surface wave or cross polarization can be reduced using a variety of techniques such as defected ground structure, 40 complementary split ring resonator, 41 substrate integrated waveguide, 42 eliminating some portion of the substrate, 14 SPP based antenna, 29 electromagnetic band gap material, 43 shorted microstrip loop, 18 metamaterial 44 and cavity backed structure, 45 reflect array, 46 single layer or multilayer corrugated antenna, 47 and many others. These approaches may also be utilized to reduce mutual coupling and improve isolation when building phased arrays and MIMO antennas.…”