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A dual-band multifunctional body-worn textile antenna is proposed. The antenna has the capability to tune its resonance frequency at its lower band, which aims for applications in the upper range of the ultrahigh-frequency (UHF) radio frequency band. At the same time, it independently operates with a fixed resonance frequency at 2.45 GHz for general communications or data transfer purpose. The antenna concept is first proposed with a single feeding port design, which achieves a frequency tuning range of 60% in the lower band. Then, an alternative configuration with two independent feeding ports is demonstrated, which is able to efficiently use the fixed frequency at the higher band. This second antenna is optimized to have an isolation of at least 15 dB between its two ports for operation with two coexisting transceiver systems. At the lower band, the fractional tuning range is approximately 37%. The two antennas are fabricated and measured to validate the design concepts.

A low-profile ( $0.035\lambda _{0}$ ) frequency-reconfigurable filtering patch antenna with a single-layered substrate is proposed in this communication. Parasitic strips and stubs are utilized to realize the filtering characteristics while using a simple probe feed. Frequency agility is implemented by adding three sets of varactor diodes on different parts of the radiating structure. These sets of varactors control the lower radiation null, the resonance frequency, and the upper radiation null, respectively. By optimizing the tuning characteristics of each set, only two biasing voltages are required, which simplifies the biasing circuit. The proposed antenna exhibits a tuning range of 21.9% with approximately 10 dB gain suppression level in its stopband, which is validated by experimental characterization.