A Review of Reconfigurable Microstrip Patch Antennas

5G/6G rapid development put forward new requirements on antenna size with multi-band in small volume, adaptive coverage, polarization diversity, MIMO operation and dynamic spectrum access. A promising solution is to employ reconfigurable microstrip patch antennas which modify the operating frequency, radiation pattern, polarization or a combination of these properties in one radiation structure. Recent advances on reconfigurable microstrip patch antennas for future wireless communication systems. In this paper, we give a literature review of recent advancements of the reconfiguration methods based on PIN diodes, varactor diodes, RF-MEMS switches, optical control, mechanical structures where these principles are applied in tunable materials. It also discusses their applications in cognitive radio, 5G/6G terminals, MIMO systems, Internet of Things (IoT) devices, wearable electronics, and beam-steering arrays and satellite communication. This paper touches salient issues such as switching and conductor losses, parasitic effects on the low-frequency dynamics, DC-bias isolation (for magnetoelectric transducers), tuning range limitations, mutual coupling and performance variation with respect to different operating states.