Design of an Advanced Filtering Antenna by Utilizing Coupling Mechanisms between Radiative and Non-Radiative Resonators

Abstract

This letter proposes a novel filtering antenna with an alternated form of radiative and non-radiative resonators. The coupling effects between radiative and non-radiative resonators are thoroughly analyzed with proposed equivalent circuit models. Within its passband, the continuous phase changes between two radiators are discussed in detail. To obtain an in-phase superposition between two radiators at central frequency, the original half-wavelength non-radiative resonator is prolonged to one wavelength. Meanwhile, the phase shifting between two radiators yields a continuous beam steering performance in the passband. With the help of the proposed circuit model, the conditions for obtaining the maximum radiation gain, the key factors affecting the antenna bandwidth, and the prediction of the scanning range are discussed. The proposed method can indeed benefit the entire design procedure quantitatively rather than qualitatively. Finally, a prototype is demonstrated and fabricated. The results show that a third-order filtering antenna is successfully designed with a relatively high gain of 9.84 dBi and a wide frequency scanning range of −29° to 21°. The proposed antenna enjoys a rather simple structure without extra feeding networks.