Scientific African (Sep 2021)
Omnidirectional antenna with modified ground plane for wideband DVB in handheld devices
Abstract
Miniaturized monopole planar antennas operating in the VHF/UHF band applied for Digital Video Broadcasting and mobile communication have gained research interest due to their low-profile, compact, and wideband nature. This antenna is capable of penetrating surfaces more easily, faster and can broadcast larger data because it operates in the wideband. The challenge of designing an antenna small enough to be adopted for Digital Video Broadcasting in handheld devices with capabilities of covering the DVB wideband and at the same time omnidirectional, with enough gain, good impedance coefficient which translates into efficiency is the drive of this paper. The proposed antenna in this paper is a rectangular patch with two large slots created in its radiating surface and extension on its edges for wider bandwidth and better matching. It employs a modified ground plane that uses coupling to achieve low return loss. CST microwave studio software was used for the simulation and optimization. The characteristics and simulated results are analyzed before the prototype structure is fabricated on an FR-4 substrate. A monopole planar antenna with total dimensions of 185 × 45 × 1.6 mm3 with an omnidirectional radiation pattern in the H-plane is fabricated and the results are presented. The antenna has high impedance bandwidth characteristics with operating frequency at -10 dB return loss from 470 MHz to 900 MHz and about 63% bandwidth efficiency. It has a VSWR ratio of less than 2. The significance of the various sections of the antenna together with the simulated and fabricated results is presented. It shows a suitable antenna with a wide operating frequency domain. The proposed antenna would be useful in Africa's development agenda in wide-area wireless communication as countries are migrating to DVB-T2 and DVB-NGH space.
