A Compact Dual-Band Foam-Based UHF PIFA

The subject of this work is a preliminary design of a low-cost linearly-polarized dual-band UHF antenna (center frequencies are 440 MHz and 915 MHz, respectively) with the bandwidth of at least 10% at 440 MHz. The antenna should be relatively small in size (at most 0.25 lambda₀), do no have a matching network (have low loss), have an almost omnidirectional radiation pattern, and be conformal (wearable). These restrictions limit the anticipated antenna type to patches (conformal TM resonators) and, maybe, to loops. Whilst the UHF loop antennas are small and have an acceptable performance close to the human body, they are narrowband and generally lossy due to the necessity of an impedance matching network