This article proposes a novel design for a patch array antenna using a double indirect coupled feeding structure to achieve broad matching and gain bandwidths for automotive radar applications. The proposed radar antenna consists of a microstrip line, an elliptical radiator, and a waveguide feeding structure. The indirect coupled feeding mechanism is first applied to the elliptical radiator, which is placed at an adjacent distance from the microstrip line. To further improve the broad matching and gain characteristics, another indirect coupled feeding structure is applied to the transition between the microstrip line and the waveguide feeding network. To verify the proposed antenna performance, including impedance matching, bore-sight gain, and the radiation pattern, the proposed antenna is measured in a compact antenna test range chamber. The results confirm that the proposed patch array antenna using a double indirect coupled feeding structure is suitable for the individual element of the 79 GHz radar array.

In this paper, we propose a design for an on-glass 5G monopole antenna for a vehicle window glass. The proposed antenna consists of a monopole resonator, an inductive line, and a co-planar waveguide (CPW), which can adjust the phase so that the current in each resonator is close to in phase. Therefore, although the vehicle window glass has a high dielectric loss, the proposed monopole with an inductive line can obtain an antenna gain that is suitable for applying to vehicle 5G communications. To verify the antenna characteristics, the reflection coefficients and the radiation patterns are measured in a full anechoic chamber. The results demonstrate that the proposed on-glass antenna is suitable for applying in vehicle 5G communications.

This paper presents a ultra-high frequency (UHF) antenna for partial discharge (PD) detection and the antenna sensor can be used near a conducting ground wire. The proposed UHF antenna has advantages of easy setup and higher-frequency detection over the high-frequency current transformer (HFCT) sensor. First, a variety of loop-shaped antennas are designed to compare each near field coupling capability. Then, a new UHF antenna is designed based on the loop-shaped antenna, which has the best near field coupling capability. Finally, the proposed UHF antenna is fabricated and measured. It provides a wide impedance bandwidth of 760 MHz (740–1500 MHz). Its simple setup configuration and wide bandwidth frequency response in the UHF band can provide a more efficient means for PD detection.

In this paper, we propose a deployable broadband mesh reflector antenna for use in signals intelligence (SIGINT) satellite systems, considering performance degradation due to shape deformation. To maximize gain by increasing the diameter of the reflector while reducing the weight of the antenna, the reflector of the antenna is designed using lightweight silver-coated Teflon mesh. The mesh reflectors are typically expanded by tension to maintain their parabolic structure; thus, shape deformation cannot be avoided. This shape deformation results in shape differences between the surface of the mesh reflector and the ideal parabolic reflector, thus resulting in the degradation of the performance of the mesh reflector antenna. To observe this degradation, we analyze antenna performance according to the number of arms, the number of joints, the feed distance, and the distance from the reflector center to each joint. The performance of the mesh reflector antenna is examined using an effective lossy conducting surface (ELCS) that has the same reflectivity as the silver-coated Teflon mesh to reduce simulation time and computing resources. The designed silver-coated Teflon mesh reflector and the double-ridged feed antenna are fabricated, and the bore-sight gain is measured using the three-antenna method. The measured bore-sight gain of the proposed antenna is 31.6 dBi at 10 GHz, and the measured and simulated results show an average difference of 3.28 dB from 2 GHz to 18 GHz. The proposed deployable mesh reflector antenna can be used in a variety of applications where small stowed volume is required for mobility, such as mobile high-gain antennas as well as satellite antenna systems. Through this study, we demonstrate that shape deformation of the mesh reflector surface significantly affects the performance of reflector antennas.

This paper proposes an all-metal Vivaldi array antenna with a wide-angle impedance matching (WAIM) layer for high-power jamming systems. To reduce fabrication complexity and time, the proposed array antenna is manufactured using a metal 3D printing method. The Vivaldi unit cell, composed of a radiating flare part and an inner cavity, is extended into an 8 × 8 array with a ±45° slant configuration. To further enhance the beam steering angle, the WAIM layer is placed on top of the proposed array antenna. The performances of the proposed array antenna, such as its active reflection coefficients (ARC), gains, and array radiation patterns, are investigated in a full anechoic chamber. At a steering angle of (θ ₀ = 45°, ϕ ₀ = 25°), the measured and simulated average ARCs of the center element (Port 36) with the WAIM layer are –13.2 dB and –18.5 dB, respectively. At 4 GHz, the measured and simulated bore-sight gains of the proposed array antenna are 19 dBi and 20.6 dBi, respectively. In addition, the measured and simulated bore-sight gains for the (θ ₀ = 45°, ϕ ₀ = 0°) steering angle in the zx -plane are 18 dBi and 21 dBi, respectively. In the zy -plane, bore-sight gains for the (θ ₀ = 45°, ϕ ₀ = 0°) steering angle are 19.3 dBi by measurement and 19.1 dBi by simulation. These results demonstrate that the proposed array antenna is suitable for high-power jamming systems because stable bore-sight gains are observed even at wide steering angles without unwanted grating lobes.