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A dual‐band dual‐mode reconfigurable antenna for on‐body and off‐body communication is presented. The antenna is operating at Industrial, Scientific, and Medical band, specifically, on‐body mode at 2.45 GHz band and off‐body mode at 5.8 GHz band. Ring slot is etched on the circular patch to form the off‐body mode with almost no influence on the on‐body mode. Three PIN diodes are utilized to act as switches between on‐body and off‐body modes. The total size of the antenna is π × 242 × 1.6 mm3. The antenna was fabricated to validate the simulation results. The antenna was measured on pork, measured results agree well with the simulated ones. The maximum measured gain of on‐body mode and off‐body mode are 0.36 dBi and 5.06 dBi, respectively. Specific absorption rate (SAR) value is less than 1.6 W/kg when the input power below 19.5 dBm which is enough for WBAN applications.

A reconfigurable wearable repeater antenna (RWRA) for wireless body area network (WBAN) applications is proposed. The RWRA can work at triple‐mode by controlling the state of PIN diodes, which are repeater, on‐body and off‐body modes. The antenna is fed by a single port at side instead of bottom for the sake of reducing the profile and improving the coupling strength between the RWRA and an implantable antenna. The total size of the antenna is π × 282 × 4.8 mm3. To validate the performance, the RWRA is fabricated and measured on minced pork. Measured bandwidths at repeater and on‐/off‐body modes are 5.8, 84, and 54 MHz, respectively. Radiation patterns are omnidirectional with vertical polarization at on‐body mode and broadside at off‐body mode, which measured peak gains are 1.2 and 5.4 dBi, respectively. Specific absorption rate (SAR) values at all three modes are analyzed in this article as well. Coupling strength between the RWRA and an implantable antenna is also measured. Besides, the effect of distance and misalignment between them are analyzed.

We report here the design and experiments of dualwideband dual-circularly-polarized (dual-CP) shared-aperture reflectarrays (RAs) operating at K-/Ka-band utilizing a single functional substrate. By coupling the adjacent but separated resonances of H-shaped aperture and circular patch and utilizing the shorted microstrip phase delay lines, the proposed RA cells can offer wideband performance. Then, these RA cells are interleaved in a shared aperture for dual-band operation. By combining the dynamic phase and Berry phase compensation techniques, the RA cells can independently control the reflective phase delay of orthogonal CP beams at both of the targeted bands, providing four degrees of freedom for beamforming. The diffractive property of an infinite periodic gradient array of the interleaved K-and Kaband cells is investigated, which verifies the wideband performance of the proposed cells. Two RAs with a thin panel thickness of 0.27 λK (λK is the free-space wavelength at K-band) are fabricated and characterized, generating symmetrically-and asymmetrically-distributed dual-wideband dual-CP beams at K-/Ka-band, respectively. The measured bandwidths for the two RAs are wider than 14.1% for K-band right-/left-handed CP beams and about 11% for Ka-band right-/left-handed CP beams with both the gain variation and axial ratio smaller than 2 dB.