An efficient analysis and optimization method is proposed to compensate the influence of asymmetric radome on an antenna by correcting amplitude and phase of the excitations. The asymmetrical and heteromorphic radomes are inevitable for the radar on high-speed aircraft. Many previous researches focused on the optimization of the radome structure and thickness to reduce the influence of radomes. However, the influence of complex streamlined radome cannot be compensated by merely optimizing the structure and thickness of the radome. Therefore, an alternative optimization method, optimizing amplitude and phase of feeds, is used in this paper. This paper adopts the active element pattern (AEP) technique, utilizing full-wave simulation method to extract the AEP for each antenna element and computing radiation patterns of array antenna by using vector composition of AEP. In combination with hybrid genetic algorithm-particle swarm optimization (HGAPSO), the antenna radiation characteristics can be obtained by updating excitations, which avoid the repeated full-wave simulation in the optimization process. Furthermore, the speed updating formula of PSO algorithm is improved combined with prior information, and the convergence speed is further increased. Finally, a 64 elements array antenna-radome system was optimized as an example in the cases of continuously adjustable phase and digital discrete phase.

According to the two-dimensional aperture principle, directivity and gain are expected to be proportional to the aperture area of an antenna or antenna array. Our simulations and measurements of an end-fire radiation antenna array overturn this conventional wisdom. The gain of an end-fire antenna array is found to be much higher than that calculated by the two-dimensional aperture principle. We introduce a length component into the two-dimensional aperture principle and propose a three-dimensional aperture principle. A four-element end-fire antenna array is designed and measured to verify the correctness of this new principle. The three-dimensional aperture principle opens a pathway to novel types of aperture utilization.

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To overcome the conflict between limited space and the requirement for high gain antennas, a novel high aperture efficiency antenna array consisting of surface wave end-fire antennas is proposed based on the three-dimensional aperture principle. By introducing longitudinal dimension into the calculation of the regular aperture antenna gain, the two-dimensional aperture principle is expanded into the three-dimensional aperture principle. Meanwhile, the directivity and gain of the array could increase without increasing the aperture area. The aperture efficiency of the array could be more than 100% in this situation. The gain of the surface wave end-fire element antenna is 9.5 dBi. The proposed 3 × 3 square antenna array with the size of 1.5λ × 1.5λ × 2.24λ obtains a gain of 15.3 dBi and its aperture efficiency reaches 120%.

Multiple standard communication networks operate in the frequency band of 1.8–6 GHz, which makes lots of antennas available in the limited space. To solve the problem of interference and improve the performance of these antennas, an ultra-wideband (UWB) antenna is presented. It consists of a boat-radiator and a dual C-shape co-radiative ground (DCCRG). One half of the DCCRG plays a role of the ground of a co-planar waveguide fed to the proposed boat-radiator antenna (BRA), while the other half works as a multiple order L-resonant circuit to broaden the lower operating band. Uniform bidirectional radiation is presented with the size of 0.25 λ × 0.375 λ × 0.0063 λ over the frequency band of 1.7–6.3 GHz (115%). The proposed antenna achieves around twice the bandwidth (60%) of the same structured antenna without the structure acting as a multiple order L-resonant circuit. Moreover, the stable boresight gain of 3.6 dBi ± 1.25 dBi is realized over the operating band.