A smart wearable textile array system (SWTAS) with direction of arrival (DoA) estimation and beamforming is proposed and developed for biomedical telemetry applications. This conformal system enables effective and continuous patient monitoring when combined with one or more health sensors, as information about the subject's health condition is received adaptively to guarantee link reliability. This operation is facilitated by a receiver front-end and a digital baseband beamforming network, which enables scalability and flexibility. The proposed SWTAS also features flexible antenna arrays made using textiles, which are arbitrarily located on a cylindrically shaped body phantom to ensure wide spatial DoA estimation capability. Besides being designed to suit on-body placement, the system performance is also characterized for on-body usage using a commercial body-emulating liquid, and placed at a realistic distance from the body, considering user clothing. Investigation indicated a good performance in the system's 80 forward plane with a DoA accuracy of 3 . Finally, a practical evaluation is presented using two transmitters placed at distinct locations and distances. The system successfully estimated both DoAs and received the telemetry signals using beamforming.Index Terms-Antenna arrays, biomedical communication, biomedical monitoring, biomedical telemetry, conformal antennas, direction of arrival (DoA) estimation, smart antennas.

This paper presents a hardware implementation of a MUSIC based DoA estimator in a practical Multiple Users Beam Tracker System (MUBTS). The robustness and accuracy of the algorithm was first checked in a much more flexible software implementation on a PC. The hardware version involves a fixed point hardware implementation in an FPGA processor, which is then integrated into the original MUBTS as a hardware acceleration, replacing the original softcored DoA estimator. The hardware accelerated MUBTS is tested and its performance is evaluated against the original one. The result is that the hardware DoA estimation processor is seamlessly integrated into the original MUBTS, reducing the iteration time of each DoA estimation from 3s to 0.3s without losing quality and ability to track moving objects.

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In this paper, a narrow-band circularly polarized (CP) microstrip leaky-wave antenna (LWA) with open stopband suppressed is proposed. Coupled meandered slow-wave lines are adopted to realize narrow-band beam scanning. The asymmetric elements are employed as radiators to realize CP and zero-crossing scanning. We modulated the antenna by loading the ground inductance and asymmetric capacitors on the meandered slow-wave transmission line. The antenna consists of ten asymmetrical structural elements connected by coupling, the antenna size of L × W is 170 mm × 25 mm. In the operating band of 8.1 to 8.5 GHz, the measured scanning angel of the fabricated antenna is from −31 to +6 . The antenna axial ratios (ARs) are all below 3 dB at the corresponding beam directions. The gain is above 9.1 dBi and the relative bandwidth is only 4.8%. In the operating band, the radiation efficiency is above 60%. It has potential applications in radar detection and wireless communication systems for its simple and low-profile structure with CP, beamscanning, and narrow-band performance.

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