This paper proposes a wideband printed patch dipole antenna with a simple on-board feeding network. The proposed antenna is composed of two dipole radiators, a transmission line, and an on-board feeding network with a chip balun. The dipole radiators are printed on a substrate, and the edges of the radiators are truncated to create a hexagonal shape with wide impedance-matching characteristics. The chip balun is embedded in an RO4003C printed circuit board (PCB) to excite differential feeding to each radiator with a 180° phase difference. The proposed antenna is optimized using a CST Studio full electromagnetic software tool, and it is fabricated and measured in an anechoic chamber. The measured fractional bandwidth for the reflection coefficient below –10 dB is 79.5%, and the proposed antenna has a measured gain of 7.1 dBi at 3.5 GHz.

This letter proposes a novel design for a printed 5G monopole antenna on a vehicle window glass. The proposed antenna consists of a coplanar waveguide (CPW), a monopole radiator, parasitic elements, and a lattice-structure reflector. The parasitic elements are placed on either side of the monopole radiator to improve the bore-sight gain. To solve the radiation pattern distortion problem that occurs due to the thick vehicle window glass, the lattice-structure reflector is printed on the opposite side of the monopole radiator. Through fabrication and measurement of the proposed antenna, it is confirmed that the design improves bore-sight gain, and minimizes the radiation pattern distortion. The results demonstrate that the proposed 5G monopole antenna with parasitic elements and the lattice-structure reflector is suitable for 5G communication in vehicle applications.

In this paper, we propose a high-durability X-band patch antenna with a coplanar waveguide (CPW) feeding network that can directly connect the upper antenna and the lower transmitting receiver modules without additional cabling. To improve the durability of the antenna, both the sub miniature push-on (SMP) connector and the feed-pin are separated through the CPW layer. This separated structure can minimize the deterioration of the antenna performance when the unwanted movement of the SMP connector occurs from external shocks. To verify the design feasibility, the reflection coefficient and radiation patterns of the proposed antenna are measured in a full anechoic chamber. The reflection coefficient of the proposed antenna is −27 dB at 10 GHz, and the operating frequency bandwidth (|Γ| < −10 dB) is 4.7% (9.82~10.29 GHz) in X-band. The proposed antenna has a maximum gain of 5.7 dBi at the bore-sight direction. In addition, the durability evaluations of the proposed design according to unwanted SMP connector movements provoked by external shocks are investigated using Monte Carlo simulations. The results demonstrate that the proposed high-durability antenna design is suitable for military ship applications that involve exposure to various external shocks.

This paper proposes a circularly polarized (CP) high-gain low-profile patch antenna using a higher-order mode with a heterogeneous layer for global positioning system (GPS) applications. To obtain theoretical insights, we analyze a CP patch using the cavity model, which has two feeding points. Radiated electric fields (E-fields) are derived from the sum of the TM ^x ₀₃₀ and TM ^x ₀₀₃ modes with a 90° phase difference at each port using a hybrid chip coupler. To verify the performance of the proposed antenna, it is fabricated and measured in a full anechoic chamber to obtain the antenna characteristics. The measured and simulated reflection coefficients of the proposed antenna are -33.1 dB and -28.3 dB at 1.575 GHz, respectively. The measured and simulated maximum gains are 9.1 dBic and 9.4 dBic at 1.575 GHz, respectively.

This paper proposes a novel miniaturized rectangular loop antenna sensor consisting of a multiturn wire and a cuboid ferrite core. The lateral surface of the ferrite core is tightly wound by the multiturn wire. To verify its feasibility, the antenna sensor is fabricated, and the antenna factor (AF) levels are measured using the three-antenna method from the very low frequency (VLF) to the high-frequency (HF) bands. The measured AF levels are 31.8 dB (with a covering plastic case) and 33.1 dB (without a covering plastic case) at 30 kHz. In addition, the proposed antenna is employed in the shielding effectiveness measurement of a small commercial cabinet to observe its suitability for shielding effectiveness (SE) measurement of small shielding enclosures. The SE values averaged over the frequency range from 10 kHz to 3 MHz are 4.1 dB and 12 dB in the horizontal and vertical polarizations, respectively.

This article proposes a method for the prediction of wide range two-dimensional refractivity for synthetic aperture radar (SAR) applications, using an inverse distance weighted (IDW) interpolation of high-altitude radio refractivity data from multiple meteorological observatories. The radio refractivity is extracted from an atmospheric data set of twenty meteorological observatories around the Korean Peninsula along a given altitude. Then, from the sparse refractive data, the two-dimensional regional radio refractivity of the entire Korean Peninsula is derived using the IDW interpolation, in consideration of the curvature of the Earth. The refractivities of the four seasons in 2019 are derived at the locations of seven meteorological observatories within the Korean Peninsula, using the refractivity data from the other nineteen observatories. The atmospheric refractivities on 15 February 2019 are then evaluated across the entire Korean Peninsula, using the atmospheric data collected from the twenty meteorological observatories. We found that the proposed IDW interpolation has the lowest average, the lowest average root-mean-square error (RMSE) of ∇M (gradient of M), and more continuous results than other methods. To compare the resulting IDW refractivity interpolation for airborne SAR applications, all the propagation path losses across Pohang and Heuksando are obtained using the standard atmospheric condition of ∇M = 118 and the observation-based interpolated atmospheric conditions on 15 February 2019. On the terrain surface ranging from 90 km to 190 km, the average path losses in the standard and derived conditions are 179.7 dB and 182.1 dB, respectively. Finally, based on the air-to-ground scenario in the SAR application, two-dimensional illuminated field intensities on the terrain surface are illustrated.