A low‐profile dual‐band shorted patch antenna with enhanced‐bandwidth and multifunctional beams under reshaped modes

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A low-profile dual-band shorted patch antenna (SPA) with bandwidth-enhancement and multifunctional beams is proposed in this article. Initially, the radiation patterns of the traditional SPA are extensively studied. It demonstrates that the radiated fields of its TM1/2,0, TM3/2,0, and TM3/2,1 modes are unsuitable to be employed for multibeam radiation. As such, a pair of shorting pins2 is loaded underneath the radiating patch, aiming to transform the broadside-beam of TM1/2,0 mode into the dual-beam. After that, a set of shorting pins3 is placed to reshape radiated fields of its TM3/2,0 and TM3/2,1 modes as the dual-beam and broadside-beam, respectively. Meanwhile, the resonant frequencies of its TM1/2,0 and TM1/2,1 modes are reallocated closely to that of TM3/2,0 and TM3/2,1 modes. With these arrangements, both of impedance bandwidth and radiation beams are enhanced under quadruple-mode resonance. Finally, the proposed SPA is fabricated and measured. The results illustrate that the microstrip patch antenna has successfully obtained an enhanced-bandwidth (|S11< −10 dB) ranging from 4.0 to 4.29 GHz and 5.24 to 5.77 GHz with two in-band attenuation poles. Besides, a small thickness of about 0.04 free-space wavelength is still maintained, while keeping single-layer and single-fed properties. Most importantly, the proposed SPA has generated desired broadside−/dual-beam radiation patterns over the operating bands.