Wideband patch antenna with enhanced gain stability for sub-6 GHz 5G applications

The increasing demand for compact, wideband and efficient antennas in 5G sub-6 GHz networks has driven research toward designs offering stable gain and high radiation performance within limited dimensions. This paper presents a gain stabilized wideband patch antenna developed through a systematic six-stage design approach incorporating circular parasitic stubs, L-slots, a meandered feed line and a defected ground structure. These elements interactively work for the provision of multi-frequency impedance matching and the introduction of resonance modes takes place with further extension of the effective electrical length of the circular parasitic stubs, whereas the L-slots are used for the perturbation of the surface currents. The meandered feed line further elongates the current path, lowering the fundamental resonance frequency by 49% without physical size increase. The defected ground structure disrupts ground plane currents, creating capacitive loading that fine-tunes impedance matching and suppresses higher order modes, collectively enabling wideband operation with minimal gain variation. The optimized design exhibits dual resonances at 3. 6 and 6. 1 GHz with return losses of − 44 and − 27 dB respectively, covering a wide operational band of 3. 2–6. 6 GHz. The antenna maintains a consistent realized gain of 2. 6–2. 7 dBi (± 0. 8 dB), radiation efficiency above 90%, group delay variation below 0. 5 ns and a low quality factor (Q 1. 44). The novelty lies in the systematic integration of these complementary techniques to simultaneously achieve wideband operation, exceptional gain stability and low group delay, making it suitable for compact 5G wireless devices.