Design of Wideband High-Gain Slotline Antennas With Enhanced Frequency Selectivity for 5G Wireless Communication Application

Achieving high gain, broadband, miniaturization, and excellent frequency selectivity in antenna design is challenging due to inherent trade-offs. This letter presents a filtering slot antenna that balances these features effectively. The design includes a central radiating slot, two sets of coupling slots with varying dimensions, four metal shorting posts, and a metal reflector. The radiating slot, fed by a microstrip, emits electromagnetic waves, while the coupling slots enhance frequency selectivity. To validate this methodology, we designed a slot filter antenna for 5G wireless communication. A size of 0.65<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\lambda _{0}\times 0.65\lambda _{0}\times$</tex-math></inline-formula> 0.26<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\lambda _{0}$</tex-math></inline-formula> (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\lambda _{0}$</tex-math></inline-formula> is the wavelength at center frequency of passband) is realized. Experimental results demonstrate that the designed antenna effectively covers the 5G operating bands of 3.3-3.8 GHz and 4.9-5.0 GHz, achieving a relative bandwidth of 56.4<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\%$</tex-math></inline-formula>. The passband exhibits a gain of 10.2 dBi, while radiation suppression of at least 15 dB is achieved within the interference bandwidths of 1710-2690 MHz and 5150-5850 MHz, respectively.