5.8 GHz 4-Channel Beamforming Tx IC for Microwave Power Transfer

Abstract

The microwave power transfer (MPT) system requires a massive Tx array for building a focused radio wave to efficiently transfer power to the Rx. Beamforming IC is one of the core elements for the massive Tx array. This paper presents a 5.8 GHz 4-channel beamforming Tx IC based on a CMOS process. The beamforming Tx IC includes a resistive 4-way power splitter, 5-bit differential phase shifters, drive amplifiers, and power amplifiers. Each channel is designed to transmit a power of no less than 100 mW. To verify the Tx IC, a 16-channel beamforming Tx module based on 16 patch antennas and four 4-channel Tx ICs was designed. The module also includes a PLL, a frequency doubler, and a 4-way Wilkinson power divider. MPT experiments to verify the beamforming IC and module were carried out using the implemented 16-channel Tx module at 5.8 GHz. Received power levels of 13 dBm and 2.1 dBm were achieved at distances of 0.4 and 1.4 m, respectively. The results are almost similar to the values acquired from the calculation using the Friis equation. INDEX TERMSMicrowave power transfer, massive Tx array, beamforming, complementary metal-oxidesemiconductor (CMOS), Tx IC.

Linear-in-dB Logarithmic Signal Strength Sensor Circuit for Wireless Power Transfer Receivers

“…A traditional LA design with NMOS as the load transistor [11] has certain advantages; for example, it is easy to adjust its gain. However, the LA shown in Figure 3 is more convenient for the proposed application, as the NMOS load transistors in the limiting cells [12] suffer from the body effect, which impacts the gain and threshold voltage [18], resulting in (i) the need for higher power supply voltages to keep the transistor in the saturation region and (ii) higher power consumption for the given specification. The LA used in our design (Figure 3) has current mirrors formed by the combination of M 3 -M 5 and M 4 -M 6 which eliminate the body effect, enabling it to operate with a low power supply.…”

“…However, these methods require a very precise alignment between the receiver and the transmitter. For drone charging, WPT systems are based on RF wave radiation in the Industry-Science-Medical (ISM) band using antenna arrays through which a radiated beam can be formed and focused on an arbitrary location or position of the receiver [18]. The WPT transmitter system comprises several key components, which include a microprocessor, a modular unit used for the up-conversion of the input signal, a phase-locked loop acting as a frequency synthesizer tasked with generating a fixed oscillating signal, filters, and a power amplifier designed to amplify the output signal and match its output impedance to the antenna.…”

Beamforming Algorithm Based on the Orthogonal Phase Bases With Trigonometric Estimation for Microwave Power Transfer Systems

“…In addition, different from LUT methods, the system can dynamically optimize the transmission phases for realtime channel characteristics. To adjust the beam weight, a simple adaptation algorithm with a fixed perturbation step size for each element was proposed [14,15]. To reduce the number of measurements required for convergence, adjusting the step size of perturbation according to the magnitude variation of the RSS was proposed [16], [35].…”

“…Eq. (15) shows that P π n can be derived using the received power levels of P + n , P − n , and P 0 . Then, from the vector diagram shown in Fig.…”

“…Because these devices require relatively low operating power, long-range wireless charging can be considered for convenience, rather than the conventional wired or short-range wireless charging methods. The MPT method has been studied for long-range wireless charging applications for these devices [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Since the MPT method uses electromagnetic wave for power transmission, adaptive beamforming using a phased array is generally adopted to increase the power transmission efficiency, and to track the Rx's.…”