No abstract

This study proposes a cylindrical conformal array antenna (CCAA) for fifth-generation (5G) micro base station applications. The CCAA is composed of five Chebyshev flexible linear array antennas (LAAs) with a circumferentially uniform arrangement on the cylindrical surface. The LAA with a logarithmic periodic arrangement is constructed by synthesizing the current amplitude distribution coefficients in elements with the Chebyshev method. The LAA with a half-power bandwidth (HPBW) wider than 76 • (−38.41 • to 38.58 • ) and a peak gain greater than 10 dBi is fabricated via the micro-electromechanical system process. Cost-performance analysis shows that five is the best number of linear arrays. To achieve omnidirectional switching scanning of the circumferential section, five LAAs wrapped on the cylindrical surface are individually excited by connecting a radio frequency semiconductor switch to the exciting ports of an eight-way power divider. Moreover, beam-switch scanning of the CCAA is measured with the aid of a standard anechoic chamber. The irradiated performance with low mutual coupling and high realized gain is verified to be irrelevant to the structural variation of various flexible experiments of LAAs wrapped around a cylindrical surface. The CCAA with beam-switch scanning operates at 26 GHz and belongs to the 5G millimeter-wave band. Results show the proposed antenna achieves omnidirectional scanning property in the H plane and has a HPBW of only 9.08 • in the E plane. The performances of the CCAA present potential advantage in flexible terminal equipment wireless communication.INDEX TERMS Beam switching, flexibility, Chebyshev linear array antenna, cylindrical conformal array antenna, millimeter wave, 5G.

A simplified notched design method for the Vivaldi antenna is exhibiting high frequency-band-selectivity characteristics. By suitably introducing half-wavelength resonator (HWR) and complementary capacitively loaded loop (CCLL), the notched-band selectivity is promoted while maintaining the wide impedance bandwidth of the antenna applicable for wireless communications. HWR is bent in the middle to focus the first notch pole, and the second notch pole is obtained by CCLL on the radiating patch. Additionally, the resonant frequency of the notched pole can be determined by the position and size of two loaded resonators in theoretical analysis, thereby realizing a wideband antenna with the desired notched band. Finally, the Vivaldi antenna of loading resonator was fabricated to verify the feasibility of this new method. Measured and simulated experimental results reveal that the antenna exhibits directional pattern in the passband, low gain at the band-rejection, and excellent selectivity within a frequency range. The simulation and measurement results are in good agreement. The proposed antenna achieves S11<−10 dB in 2.6–13.7 GHz and a notch band from 4.49 to 6.64 GHz to reject IEEE 802.11a and HIPERLAN/2 frequency band. Moreover, the proposed antenna has good frequency selectivity, and its gain is good enough in the passband with peak gain up to 10.8 dBi. This antenna design presents frequency suitability, demonstrating that a UWB antenna with a controllable notched band has been realized.