According to the nonlinear response characteristics of magnetron, this article proves that a 2.45 GHz band continuous-wave magnetron can perform as a modulator in communication system. The intermediate frequency (IF) signal coupled to the power supply of magnetron, as the ripple of anode voltage, can be modulated to a nearby band centered on the resonant frequency of magnetron. We deduced the output expression of free oscillating magnetron under the influence of anode voltage ripple. And electromagnetic simulation was accomplished to testify the validity of the theoretical derivation. Moreover, we designed the circuit to couple signal with frequencies of 2, 3, and $4$ MHz to the anode voltage. The output spectrum of magnetron changed as the frequencies were tuned, to satisfy the frequency requirements for modulating. Finally, a simultaneous information and power transfer system based on a magnetron combined with the power supply coupling circuit was developed and tested. This system achieved the modulation, amplification, transmission, and demodulation of low-frequency signal which is equivalent to human voice. This research reveals that the proposed techniques have great potential for future simultaneous wireless information and power transfer (SWIPT) system because they provide higher power at lower cost.

A compact circularly-polarized (CP) rectenna based on wide-slot antenna is designed at 5.8 GHz. The feed-back wide-slot antenna is used for its broadband, easy-to-integrate circuitry, simple structure, and low sidelobes. The designed receiving antenna has a bandwidth of 31.8%. In order to minimize the profile of the rectenna, the rectifier is integrated on the back side of the substrate with a matching circuit and a DC-pass filter. It features stable conversion efficiency on three azimuthal planes. The maximum efficiency of 66.2 % and an output DC voltage of 6.33 V have been measured with a 900 Ω load at the power density of 11.4mW/cm2. A 5 $\times$ 5 rectenna array is built for large physical aperture and increased output power. The maximum conversion efficiency of 62 % is observed with the array. Taking the advantage of immunity to misalignment of the CP antenna, the proposed rectenna and array are suitable to be used in mobile applications for wireless power transfer (WPT).

Microwave selective/localized heating has been widely used in special areas, e.g., medical treatment and food processing, but the control of selective/localized heating in restricted space, e.g., microwave ovens, is difficult to accomplish. In this article, a Giuseppe Peano fractal phased-array antenna is designed, and the phase of each radiator is derived to achieve the arbitrary spatial division of the electromagnetic field in a cavity based on the superposition principle of waves. Then, a multiphysics model of microwave heating is established by coupling the electromagnetic field and heat transfer to simulate the directional control of microwave heating in a cavity. An experimental system is built, and the heating results are measured using an infrared thermal imager to verify the temperature distribution in different spatial regions. Finally, the feasibility of the model for different heating targets is discussed.