Search

In this paper, a single‐layer filtering antenna based on half‐mode patches is proposed. It consists of a main driven patch and a parasitic patch. A U‐shaped slot is first etched on the main driven patch to generate a new resonant mode and a radiation null simultaneously. Four pairs of shorting pins are introduced on the main driven patch to raise its operating frequency to near that of the U‐shaped slot, thus broadening the impedance bandwidth (IBW). Additionally, a parasitic patch is introduced near the driven patch to introduce an extra half‐TM10 mode and an extra radiation null, significantly enhancing the IBW and the upper‐edge selectivity of the antenna. A prototype was fabricated and tested for validation. It achieves a peak realized gain of 6.55 dBi and −10‐dB IBW of 8.8%, and exhibits good out‐of‐band rejection performance while maintaining a low profile of 0.017 λ0 and a compact transverse size of 0.29 λ02. [ABSTRACT FROM AUTHOR]

A compact low‐profile planar filtering antenna with an enhanced suppression level is presented in this paper. The presented antenna has a simple structure, consisting of an E‐shaped driving patch, a shorted parasitic patch, and a defected ground structure (DGS). The E‐shaped driving patch serves as an effective radiator and facilitates the filtering response. The shorted parasitic patch is horizontally arranged and coupled with the driving patch through the radiating edge. And a radiation null and an extra in‐band resonance can be generated, which would simultaneously broaden the impedance bandwidth and improve the suppression level. In addition, a DGS on the metalized ground plane is etched to introduce another radiation null, and the out‐of‐band suppression level would be significantly enhanced. The filtering antenna with a center frequency of 3 GHz was constructed and tested to verify its performance. The measured values, which indicate a bandwidth of 10% (2.85–3.15 GHz) and a peak realized gain of 5.2 dBi, are in agreement with the simulated values. The presented filtering antenna features a low profile of 0.016λ0, a compact antenna size of 0.16λ20, as well as an improved suppression level of more than 22 dB. [ABSTRACT FROM AUTHOR]

In this letter, a compact circularly polarized (CP) microstrip patch filtenna designed by reusing dual‐mode substrate integrated waveguide (SIW) cavity is proposed. The dual‐mode SIW cavity, operating at its TE120 and TE210 modes, can be used not only as the first stage resonator of the filtering network but also feeds the four microstrip patches working at their TM10 and TM01 modes. A pair of asymmetric perturbed posts is inserted in the SIW cavity to perturb the electric field distributions of TE120 and TE210 modes so as to achieve one axial ratio (AR) minima. The other AR minima is realized by sequentially exciting the four orthogonal microstrip patches via the four rectangular slots that are etched on the top surface of the SIW cavity. In addition, four metal posts penetrated the SIW cavity is employed to improve the impedance matching. For verification, a CP filtenna prototype centered at 5.13 GHz is designed, manufactured, and tested. The measured results agree well with the simulated ones, demonstrating a fractional impedance bandwidth of 6.9% (4.95–5.3 GHz), a 3 dB AR bandwidth of 4.2% (5–5.21 GHz), and a maximum boresight realized gain of 8.4 dBic. [ABSTRACT FROM AUTHOR]