Dual-Polarized Wearable Antenna/Rectenna for Full-Duplex and MIMO Simultaneous Wireless Information and Power Transfer (SWIPT)

<div>Owing to the mobility of a wearable antenna and the unpredictable body-centric communications environment, dual-polarization antennas are essential for both communications and energy harvesting. This paper presents a dual-polarized four-port textile antenna/rectenna for wearable simultaneous wireless information and power transfer (SWIPT) applications. The proposed antenna utilizes dual ports for both off-body communication and energy harvesting from horizontal and vertical polarizations. The antenna maintains a 100 MHz bandwidth with an S11 under -10 dB around 2.4 GHz in the presence and absence of the human body, and at least 10~dB small-signal and large-signal isolation between all ports. The antenna maintains a 70-88% measured total efficiency and 8.4--9.6 dBi gain for various on-phantom positions across both communication ports. The measured mutual coupling is under -10 dB between co-polarized rectenna/antenna ports, and under -16~dB between orthogonally-polarized ports. A high RF to DC peak power conversion efficiency of over 70% (+-5%) is achieved with a broadside harvesting pattern. Based on the proposed antenna's performance, SWIPT microstrip antennas can be adopted for both full-duplex and MIMO applications, significantly reducing the complexity of future battery-free networks for both wearable and non-wearable applications.</div>

Dual-Polarized Wearable Antenna/Rectenna for Full-Duplex and MIMO Simultaneous Wireless Information and Power Transfer (SWIPT)

<div>Owing to the mobility of a wearable antenna and the unpredictable body-centric communications environment, dual-polarization antennas are essential for both communications and energy harvesting. This paper presents a dual-polarized four-port textile antenna/rectenna for wearable simultaneous wireless information and power transfer (SWIPT) applications. The proposed antenna utilizes dual ports for both off-body communication and energy harvesting from horizontal and vertical polarizations. The antenna maintains a 100 MHz bandwidth with an S11 under -10 dB around 2.4 GHz in the presence and absence of the human body, and at least 10~dB small-signal and large-signal isolation between all ports. The antenna maintains a 70-88% measured total efficiency and 8.4--9.6 dBi gain for various on-phantom positions across both communication ports. The measured mutual coupling is under -10 dB between co-polarized rectenna/antenna ports, and under -16~dB between orthogonally-polarized ports. A high RF to DC peak power conversion efficiency of over 70% (+-5%) is achieved with a broadside harvesting pattern. Based on the proposed antenna's performance, SWIPT microstrip antennas can be adopted for both full-duplex and MIMO applications, significantly reducing the complexity of future battery-free networks for both wearable and non-wearable applications.</div>

Four-Port Dual-Mode Diplexer with High Signal Isolation

An ease of four-port dual-mode diplexer with high signal isolation is presented. A compact dual-mode diplexer with high signal isolation between the Rx and Tx modules is achievable by only using one resonator filter topology. Two back-to-back dual-mode diplexers have a 180° phase shift in one branch. The high isolation can be achieved by amplitude and phase cancellation technique. The delayed transmission line can be easily achieved by the phase shifter. The simulated and measured four-port dual-mode diplexers are designed at the centre frequency of Rx/Tx at 1.95 GHz and 2.14 GHz, respectively. The measured results of Rx/Tx dual-mode diplexer devices are presented with 47.1 dB Rx/Tx isolation. This four-port dual-mode diplexer achieves the isolation (S32) of more than 24.1 dB when compared with the conventional three-port dual-mode diplexer structure.

Applied methods of power supply and galvanic isolation of gate drivers of power transistors in bridging end stages of Class D amplifiers and inverters

Various methods used for a floating high-side gate drive power supply and galvanic isolation of the Class-D amplifiers and different DC-AC or DC-DC converters have been reviewed and evaluated in the paper. On the basis of the literature, the bootstrap floating supply and self-boost charge pump topology for a gate drive high-side power supply, as well as control signal isolated systems with optically-isolated signals or with capacitive signal isolation have been described and compared. New topologies of the Class-BD amplifiers with Common-Mode (CM) free outputs using PSC PWM - Phase Shifted Carrier Pulse Width presented in the paper, shows that almost all gate drivers of the output stage transistors require floating power supply and galvanic isolation of the control signals. In the case of such circuits with multi-level PWM output, the most reliable and robust method for the floating gate drive power supply and galvanic isolation is self-boost charge pump topology with capacitive control signal isolation. Correct operation of the output stage of the proposed Class-BD amplifiers as well as the PWM modulator and self-boost charge pump topologies with capacitive control signal isolation have been verified using intensive Pspice simulation.