Low-Radar Cross Section antennas attract substantial attention in Stealth Technology. The Radar Cross Section reduction performance of the microstrip antennas should be improved since they contribute to the overall Radar Cross Section. A novel microstrip patch antenna with a polarization converter metasurface is proposed to extend the Radar Cross Section (RCS) reduction bandwidth. The metasurface uses metallic strip structures to obtain the required polarization conversion for Radar Cross Section reduction. The proposed patch antenna shows the overall RCS reduction bandwidth of 7.25 GHz-24.83 GHz (110%) as compared to the metal sheet and the Reference Patch antenna. 10 dB RCS reduction is obtained from 8.33 GHz-9.16 GHz (9.49%) and from 12.81 GHz-18.85 GHz (38.16%) as compared with the Reference Patch antenna. The RCS reduction of the antenna and the antenna radiation patterns are verified by numerical simulations and experimental observations. The main novelty of the proposed design is its wideband RCS reduction for Transverse Electric as well as Transverse Magnetic polarization with enhancement in antenna radiation pattern parameters. Significant RCS reduction can also be obtained for oblique incidence.....

Magnetic coupling detection method, as one of the methods of solving grounding grid breakpoint location problem, has the problem that the size of the transmitting coil is too large to be easily applied to the actual environment detection. In order to reduce the size of the transmitting coil and ensure the effect of breakpoints detection, this paper studies the characteristics of the planar coil based on the method of grounding grid breakpoint magnetic coupling detection. Firstly, a mathematical model of the planar coil magnetically coupled detection grounding grid breakpoint system under high frequency is established. After analyzing the model, factors of affecting the breakpoint detection effect and the high frequency characteristics of the system are derived. Secondly, a simulation model of the magnetically coupled detection grounding grid is established by using HFSS software. The influence of the line width, side length, number of turns and turn spacing of the transmitting coil on the detection effect is studied in detail. Besides, according to the law, the coil size optimization design is carried out. At last, the experimental platform is built to verify the reliability of the simulation and theory. The results show that the detection effect decreases as the line width and side length of the planar coil decrease, but the effect of line width change is small. Increasing the number of turns and turn spacing can improve the coupling coefficient to increase the detection effect, but when the distortion region is located after the parallel resonance point, the distributed capacitance will greatly inhibit the detection effect.....

This paper presents the design, co-simulation, and measurement of a two-stage broadband-cascaded low noise amplifier (LNA) using resistive terminated architecture. This architecture extends the bandwidth of a low-noise amplifier while maintaining a low NF and high flat gain S₂₁. The LNA is designed with planar technology and mounted on an FR4 substrate. The used InGaAs HEMT MGF4918D transistor from Mitsubishi technology has very low noise and operates up to 18 GHz. The reflection coefficient results of the studied LNA are lower than -10 dB. The stability is unconditional over the entire operating band. The measured gain is 14 dB ± 0.75 dB with a minimum NF noise figure of 2.9 ± 0.4 dB. The group delay is 0.605±0.145 ns. The 1 dB compression point is 10.16 dBm, and the third order input intercept point IIP3 is 14.25 dBm. Two-stage cascaded LNA has a total power consumption of 164 mW and occupies an area of 7x1.3 cm².....

In this letter, a near-field focusing method for generating patterned focusing is studied. A partially excited planar array antenna is proposed for patterned focusing, which effectively suppresses the side lobes of the focusing pattern. The phase of the array antenna is adjusted by a digital phase shifter. A prototype was made and tested to verify the effectiveness of the method. Both the full planar array and the partially excited array realize the ``.'' pattern, and the partially excited array effectively reduces the side lobes. The experimental results show that the method can achieve focusing in any area. This study can provide a reference for wireless energy transfer and microwave hyperthermia. ....