ABSTRACT
Microstrip antennas are widely employed in communication systems and seekers. Microstrip antennas posse’s attractive features that are crucial to communication and medical systems. Microstrip antennas features are low profile, flexible, light weight, and have low production cost. In addition, the benefit of a compact low-cost feed network is attained by integrating the radio frequency (RF) front end with the radiating elements on the same substrate. Microstrip antennas have been widely presented in books and papers in the last decade [1-7]. However, the effect of the human body on the electrical performance of wearable antennas at 434 MHz is not presented [8-13]. RF transmission properties of human tissues have been investigated in several articles [8,9]. Several wearable antennas have been presented in the last decade [10-14]. A review of wearable and body-mounted antennas designed and developed for various applications at different frequency bands over the last decade can be found in Ref. [10]. In Ref. [11] meander wearable antennas in close proximity of a human body are presented in the frequency range between 800 MHz and 2700 MHz. In Ref. [12] a textile antenna performance in the vicinity of the human body is presented at 2.4 GHz. In Ref. [13] the effect of the human body on wearable 100-MHz portable radio antennas is studied. In Ref. [13] the authors concluded that wearable antennas need to be shorter by 15%–25% from the antenna length in free space. Measurement of the antenna gain in Ref. [13] shows that a wide dipole (116 × 10 cm) has a –13 dBi
gain. The antennas presented in Refs. [10-13] were developed mostly for cellular applications. Requirements and the frequency range for medical applications are different from those for cellular applications.
