Reverberation chambers (RCs) were recently reported as a low-cost alternative to anechoic chambers (ACs) to perform radar cross-section (RCS) pattern measurements. The method consists i, using transmitting and receiving antennas pointing towards a target under test placed on a rotating mast. As a classical RCS characterization, the echo signal is analysed based on two measurements with and without the target in the RC. In the hypothesis of an ideal diffuse field generated in the RC, this signal difference appears as the echo signal hidden in a Gaussian noise. In case of a point-like backscattering target, observing this signal over a given frequency bandwidth allows the identification of the target response as a sinusoidal signal over this bandwidth whose period is related to the antenna-target distance measured from the measurement calibration plane positions. Therefore, the extraction of the magnitude of this sinusoidal signal requires a proper estimation of this distance. Furthermore, a sinusoidal regression processing relies on the approximation of a constant envelope over the selected frequency bandwidth, imposing some restrictions. In this paper, we introduce a two-step method that consists in identifying the most appropriate distance according to the target's orientation before estimating the magnitude of the sinusoidal signal. We highlight the improvement of RCS estimation on a point-like back-scattering target compared to the one-step procedure applied so far. In addition, it is shown that the analysis performed regarding the estimated distance provides a physical insight into the position of the equivalent backscattering point.....

The paper focuses on the design, measurement, and performance analysis of a high-gain cross-orthogonal series fed two dipole antenna (STDA) arrays with side-wall reflectors. The antenna is specifically designed for 4G Long Term Evolution (LTE) and sub-6 GHz 5G band applications. The designed antenna is capable of operating at multiple frequencies aiming to support 4G LTE and the sub-6 GHz 5G application bands. To improve the radiation characteristics and prevent coupling effects in the presence of side-wall reflectors, parasitic strip pair directors are included in the antenna design. Furthermore, the performance of the designed STDA is evaluated by forming different array configurations, such as 2×1, 2×2, and 2×3 arrays. The various array configurations are proposed to investigate the effect of the projected array arrangements on the radiation pattern, impedance bandwidth, and gain characteristics. The results of the measurements show that the radiation characteristics of the antenna has improved significantly. The proposed antenna operates at six distinct frequencies for S₁₁≤-10 dB. The operating frequencies at 1.8, 2.35, and 2.6 GHz can be utilized for LTE and 3.2, 4.2, and 5.2 GHz can support sub-6 GHz 5G bands. The antenna is characterized by its compact size, measuring around 89 mm × 71 mm, while still achieving high gain of 12.3 dB for single STDA element with parasites and with reflector. These results emphasize the importance of the proposed design, which incorporates parasitic strip pair directors and side-wall reflectors. This design methodology plays a crucial role in enhancing the performance of the prescribed STDA array for both 4G LTE and sub-6 GHz 5G applications.....

Low Energy (LE) devices for communication systems like Bluetooth, 5G New Radio (NR), etc. are most likely to be powered by a battery, however, the limitation of the utilization time of this power supply entails it to be handled in different way; one of them is using electromagnetic energy harvesting paradigm, which could be capable to supply the energy consumption of this device. In this research it is presented the design and implementation of a device for radio frequency energy harvesting in the Industrial, Scientific and Medical (ISM) band. As first step, field intensity measurements in ``Facultad de Informatica y Electronica'' (FIE) were performed by the utilization of NARDA SRM 3006 radiation meter, with the aim of determining the technology with highest radio frequency (RF) energy within the 2.4 GHz ISM band. After the analysis, the chosen was WiFi technology due to the massive implementation that exists in the surroundings. Therefore, the frequency of 2.45 GHz was selected as the center frequency for the design. The device was implemented using FR4 Epoxy glass material with a dielectric permitivity of 4.4 and a dielectric thickness of 1.6 mm. The device consists of 3 stages: i) Capturing energy using a microstrip patch antenna ii) Rectification using a coupling network followed by a rectifying circuit and iii) Energy storage using the method of harmonic balance and electromagnetic moment. Finally, harvesting measurements were carried out in FIE's laboratory; the RF energy of a WiFi router was harvested and at 10 cm a voltage of 510.6 mV was obtained, this level of voltage was capable of turning on a led diode demonstrating the functioning of the device.....

Conventional solid-state plasma devices encounter limitations in terms of the concentration and distribution uniformity of solid-state plasma, which adversely affects their microwave characteristics and overall antenna system performance. In this study, we propose a novel heterogeneous SPIN diode with multi-region compensation effects aimed at addressing this challenge. By incorporating SiGe regions within the intrinsic region of the device, we enhance the carrier injection ratio, effectively compensating for the rapid attenuation of solid-state plasma. As a result, a high-concentration and uniformly distributed solid-state plasma region is achieved within the SPIN diode, surpassing a concentration threshold of 1×10¹⁸ cm^-3 within the intrinsic region. Through extensive simulations utilizing Sentaurus TCAD software, we demonstrate notable improvements in plasma concentration, distribution uniformity, and other key electrical parameters compared to traditional devices. The presented findings mark significant advancements in the realm of silicon-based plasma devices and hold promise for reconfigurable antenna systems.....