Near field interaction of microwave signals with a bounded plasma plume

The objective was to study the effect of the arcjet thruster plume on the performance of an onboard satellite reflector antenna. A project summary is presented along with sections on plasma and electromagnetic modeling. The plasma modeling section includes the following topics: wave propagation; plasma analysis; plume electron density model; and the proposed experimental program. The section on electromagnetic modeling includes new developments in ray modeling and the validation of three dimensional ray results

Loop-Type Ground Radiation Antenna for a C-Shaped Ground Plane

In this study, optimum locations for a loop-type ground radiation antenna are evaluated for C-shaped ground planes of two different sizes. To achieve good radiation performance, the antenna needs to be located such that it couples with the dominant current mode of the ground plane. Antenna locations are proposed using the characteristic mode analysis of the ground planes. The measured bandwidths of the antennas at the proposed locations have more than twice the bandwidths of the cases in which the antennas are coupled with non-dominant modes. The operating frequency of the antennas is 2.45 GHz

A Compact MIMO Antenna Design Using the Wideband Ground-Radiation Technique for 5G Terminals

This paper introduces a 4 × 4 multiple-input and multiple-output (MIMO) antenna application based on the conception of the characteristic mode of 5G terminals. The proposed antenna used a series capacitor and a parallel capacitor to control input impedance matching, while the resonance frequency was controlled by employing a resonance loop capacitor. In this way, we achieved a compact miniaturization antenna that uses ground radiation for the target 5G New Radio (NR) operating bands with n48, n77, and n78 bands. The simulation and measurement data revealed that the −6 dB bandwidth of the proposed antenna was approximately 1,240 MHz (ranging from 3.14 GHz to 4.38 GHz), while the efficiency also improved from 38.7% (reference) to 49.1% (proposed) within the 3 GHz to 4.6 GHz range. Furthermore, the radiation pattern exhibited satisfactory radiation performance. Therefore, it was concluded that the proposed 4 × 4 MIMO antenna set technology has promising prospects for application in 5G communication terminals in the future

Ground Radiation Antenna for Mobile Devices Using Controlled Endless Metal Rim Mode

In this paper, we introduce a ground radiation antenna that uses controlled endless metal rim modes. In the proposed technique, the metal rim mode is tuned and excited as a one‐wavelength radiator by a small ground radiation antenna. The proposed antenna occupies a clearance of 1 mm × 4 mm in a 30 mm × 20 mm ground plane. A metal rim with dimensions of 34 mm × 24 mm surrounds the ground plane, and the metal rim is separated from the ground plane by a gap of 2 mm. In addition, a lumped capacitor is inserted between the metal rim and the ground plane to control the characteristic mode of the metal rim such that the resonance of the metal rim is tuned to be equal to the operating frequency. By performing simulations and measurements, we compare the performance of the proposed antenna with that of a reference antenna that does not have an inserted capacitor between the metal rim and the ground plane. The results show that a significant improvement of the radiation performance is obtained by employing the proposed technique