Design of Elliptical Patch and Half-Circular Ground Microstrip Antenna with CPW-Fed for Chamber Applications

This study designed an elliptical patch microstrip antenna with CPW-Fed to test wave-absorbing materials on the inner chamber walls at a wideband frequency. To achieve the required frequency range, calculations were performed for the dimensions of the patch and the impedance line. The antenna has dimensions of $60 \times 62 \mathrm{~mm}$ and uses FR-4 material with a substrate thickness of 1.6 mm, a copper thickness of 0.035 mm, and a relative permittivity of 4.3. The antenna was initially designed with a rectangular ground, but testing results showed limited bandwidth. To improve the performance, the ground was modified into a half-circular, and the curvature of the ground was optimized. The best results were achieved with a curvature ground of 14 mm and the antenna operating frequency ranging from 1.81 GHz to 18 GHz, with a minimum peak value at -49 dB. The radiation pattern measured in the elevation angle at a theta 0 degrees produced a maximum radiation of $\mathbf{- 1 3. 6} \mathrm{dBi}$ parallel to the antenna plane, with a relatively large half-power beamwidth (HPBW). The antenna gain is in the range of $\mathbf{2. 5}$ to 5 dBi. Although the antenna gain is relatively low, the antennas are suitable for testing absorbing materials on the inner chamber walls, considering the wide bandwidth aspect and the medium chamber size.