Reply to Comments on “Wideband Radiation Reconfigurable Microstrip Patch Antenna Loaded With Two Inverted U-Slots”

Abstract

We appreciate the comments given in [1] on active scattering parameters and realized gain of the antenna in [2] . In this correspondence, we would like to address the aforementioned parameters, which were simply overlooked in [2] , by slightly modifying the antenna structure in [2] . The resultant antenna is now capable of radiating both the broadside and conical patterns over a 45% active impedance bandwidth, which is still much greater than that of the microstrip patch antennas with reconfigurable radiation patterns reported in [3] – [13] . The modifications to [2] to improve the isolation between the two ports include incorporating an H-shaped stub, inspired by the one in [14] , at the center of the patch, as shown in Fig. 1(a) , and placing shorting vias at appropriate positions on the antenna, which extends from the top layer of the patch to the ground plane. These vias, along with the narrow slits at the center of the patch, considerably aided in reducing the mutual coupling between the probes. The H-shaped stub and the shorting vias on it facilitated in improving the impedance matching. In the interest of maximizing the overall active reflection coefficients of both the modes of operation, i.e., SUM and DIFFERENCE modes, L-shaped probes are used to excite the antenna structure in lieu of the SMA probes. To integrate the L-probes, the profile of the antenna is now increased from $\sim 0.02\lambda _{\mathrm {d}}$ to $\sim 0.08\lambda _{\mathrm {d}}$ , where $\lambda _{\mathrm {d}}$ is the dielectric wavelength at the center frequency of operation.