A low-profile internet of things-controlled frequency reconfigurable triple band antenna for microwave sensing applications

This paper presents the design and analysis of IoT (Internet of Things) controlled frequency reconfigurable triple-band antenna for WiMAX, ISM (Industrial, Scientific, and Medical) band, and X band microwave sensing applications. The designed antenna is constructed on polyimide substrate with a limited ground plane with compact dimensions of 27.5?×?8?×?0.6 mm³. The fabricated antenna is sensing the microwave signals that fall under WiMAX, ISM, & WLAN, and X band with a tunable frequency range of 3.2–3.9, 5.1–6.5, and 8.2–12 GHz, respectively. The operating frequency bands can be tuned by PIN diodes and which will be controlled by using the IoT-based NodeMCU module. The designed antenna resonates at 3.5, 5.9, and 8.45 GHz when the PIN diodes are in ON state and resonating at 3.79, 5.8, and 10.48 GHz when PIN diodes are in OFF state. The proposed antenna has bidirectional radiation at upper-frequency bands and unidirectional at lower frequency bands with gain ranging from 2.2 to 3.25 dB. The proposed frequency reconfigurable triple-band antenna has a more than 90% radiation efficiency at all the operating frequencies in the ON state. A good similarity between the measured (Antenna measurement setup with Vector Network Analyzer) and simulated results (CST Microwave Studio) is observed. In the real-time environment, the proposed reconfigurable antenna is tested by the CDAC (Centre for Development of Advanced Computing, India) Cmote unit found its suitability to microwave sensing applications.