ISM band

Engineering

Loop antenna

Materials science

Antenna tuner

Antenna (radio)

Acoustics

Reconfigurable antenna

Multi-band device

Substrate (aquarium)

Directional antenna

Geology

Oceanography

Electrical impedance

Coaxial antenna

Physics

Wideband

Antenna measurement

Optics

Patch antenna

Microstrip antenna

Antenna factor

Dipole antenna

Optoelectronics

Electrical engineering

IEEE Transactions on Antennas and Propagation

This communication presents a compact wideband implantable loop antenna with circular polarization (CP) characteristics at 920 MHz industrial scientific and medical (ISM) (902-928 MHz) band and 2.45 GHz ISM band (2.40-2.48 GHz). To widen the impedance bandwidth (IBW) and improve the axial ratio (AR) behavior of the antenna, a reactive impedance substrate (RIS) is exploited. Meandering each arm of the loop makes the antenna compact in size, while the generation of surface wave by the RIS and open-ended configuration of the antenna collectively renders circular polarized wave. The performance of the antenna is analyzed using a single-layer skin model and other existing phantom models. The key feature of the proposed antenna is its dual-band CP behavior, which persists even at the flexion deformation of the human skin. An IBW of 123% with a 3 dB AR bandwidth of 15% and 8.7% is obtained at the planar state of the skin implantable antenna. To validate the simulated results, in vitro measurements were experimentally performed. Also, to find the maximum transmission range of the antenna for biotelemetry communication, the link margin has been analyzed. Finally, to use the antenna inside the biomedical device, the effect of microelectronic components is investigated.

Dual-Band Circular Polarized Flexible Implantable Antenna Using Reactive Impedance Substrate