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For integrated design of a filter and an antenna, a wideband circularly polarized (CP) dielectric resonator antenna (DRA) with filtering characteristics is proposed. A rectangular slot structure is etched on the ground to optimize the axial ratio (AR) bandwidth of the antenna singly fed by one port. Capacitive filtering branches are combined into the microstrip feeding line to effectively generate two radiation nulls outside the passband. To further enhance the suppression level in the high-frequency stopband, the stair-shaped DR is chamfered into a fish-shaped structure. A suppression level larger than 15 dB is found within the stopband. A prototype of the antenna is fabricated, and both of the simulated and measured results show a wide bandpass filtering performance over the operating frequency band. The antenna has an impedance bandwidth of 37.8%, an AR bandwidth of 25.1%, and a low profile of 0.078λ0 (λ0 is the free-space wavelength at 5.47 GHz), which can be a good candidate for 5 G and WLAN communication systems. [ABSTRACT FROM AUTHOR]

A novel dual-band dual circularly polarized antenna array is proposed for vehicle satellite communication systems. The dual-band filtering element is presented, in which the dual-band characteristics are realized by vertically feeding method. The ring-shaped frequency selective configurations (RFSC) are added to the feeding network for the filtering function. The sequential rotation array is achieved by rotating four identical antenna elements around z-axis, where the phase difference of adjacent elements is 90° or −90° for the left-hand circular polarization and right-hand circular polarization, respectively. A decoupling approach is introduced to change the current paths on the surface of radiator with cutting orthogonal slots, which solves the problem of serious coupling between the different elements of the sequential rotation array. The prototype is fabricated and measured to verify the reliability of the simulations, and the simulations and measurements have reasonable consistency. The impedance bandwidths of the array are 7.26–7.46 GHz and 8.07–8.36 GHz, respectively. The port isolation of the array is greater than 30 dB in the two bands. The axial ratio (AR) bandwidths are 7.12–7.48 GHz and 8–8.36 GHz, respectively. The designed array has a promising application prospect for vehicles to satellite communications. [ABSTRACT FROM AUTHOR]

A novel scheme of an electrically tunable microstrip patch antenna using an electroactive polymer Poly(vinylidene fluoride-trifluoroethylene) thin film as a part of substrate is presented. The suited plus DC power supply is produced and applied to adjust the permittivity of the Poly(vinylidene fluoride-trifluoroethylene) film, which is imposed directly on the copper patch of the antenna. The patch is designed to be the same size as the ground plane to guarantee the plus static electric field inside the film uniformly. With the proposed structure, an electrical frequency agile microstrip patch antenna that performs well is achieved. The measured results demonstrate that the resonant frequency can be unceasingly tuned from 3.72 to 4.025 GHz; when the DC voltage changed from 0 to 430 V, a frequency tuning range of 7.57% is obtained. [ABSTRACT FROM AUTHOR]