Terahertz detector utilizing a SiO2/Graphene/SiO2 sandwich suspended at the feed of a planar antenna

We report on the fabrication of a terahertz detector utilizing a SiO2/graphene/SiO2 sandwich suspended at the planar antenna feed. This design of the detector aims to enhance its sensitivity via weakening of the heat sink between graphene’s phonons and those of the substrate. We achieve complete suspension of the sandwich only in case of a low fill-factor of the antenna feed area. Evaluated DC parameters of the samples are consistent with those reported in the literature. The fabrication process developed is suitable for implementing the detector proposed for signal frequencies up to several terahertz.

Square Waveguide Polarizer with Diagonally Located Irises for Ka-Band Antenna Systems

This article presents the results of development and optimization of a new square waveguide polarizer with diagonally located square irises. The application of suggested geometrical modification of irises form and location instead of a standard wall-to-wall irises configuration allows to exclude 45-degree twists between wideband waveguide polarizer and orthomode transducer of a dual-polarized antenna feed system. In addition, a waveguide polarizer and polarization duplexer can be manufactured by milling technology as two single details, which makes the proposed engineering solution reliable, simple for simulation, development and application. Suggested new polarizer design was developed for the satellite operating Ka-band. It contains 12 irises, which are symmetrically located in the diagonal corners of a square waveguide. Obtained optimal polarization converter provides excellent matching and polarization performance. The maximum level of VSWR is less than 1.04 for both orthogonal polarizations. Values of cross-polarization discrimination are higher than 32 dB in the operating Ka-band. Developed square waveguide polarizer with diagonally located irises can be applied in modern wideband satellite antennas.

Special beamforming by means of a semi-spherical Lüneburg lens

The paper considers a semi-spherical Lüneburg lens with a conductive shield. In certain conditions a lens of such design may form radiation patterns without the side lobe or cosecant-type patterns. Such radiation patterns can be formed by controlling the following parameters: antenna feed angle, conductive shield diameter, dielectric substrate thickness. The paper focuses on particular cases of obtaining special-type radiation patterns.

Deployment mechanism for nanosatellite dipole antenna

The paper focuses on the design of the deployment mechanism for a nanosatellite with a fusible element. The main requirements for this mechanism were: relative simplicity of design, reliability, as well as simplification of the ground testing procedure. Using the principle of fixation on fusible elements, Rose’s alloy in particular, we designed a laboratory prototype of the antenna feed deployment mechanism for CubeSats. Furthermore, we developed a technology of flap deployment control by measuring the conductivity of the fusible element. We carried out a set of tests of the created laboratory prototype on a vibration stand and in a thermal vacuum chamber, as well as a series of functional tests. Comparison of the created prototype with the closest commercial analogs showed that a significant gain in the dimensions of the structure was achieved, as well as the number of elements of the mechanism itself was reduced, which positively affect reliability.

New Compact Wearable Metamaterials Circular Patch Antennas for IoT, Medical and 5G Applications

The development of compact passive and active wearable circular patch metamaterials antennas for communication, Internet of Things (IoT) and biomedical systems is presented in this paper. Development of compact efficient low-cost wearable antennas are one of the most significant challenges in development of wearable communication, IoT and medical systems. Moreover, the advantage of an integrated compact low-cost feed network is attained by integrating the antenna feed network with the antennas on the same printed board. The efficiency of communication systems may be increased by using efficient passive and active antennas. The system dynamic range may be improved by connecting amplifiers to the printed antenna feed line. Design, design considerations, computed and measured results of wearable circular patch meta-materials antennas with high efficiency for 5G, IoT and biomedical applications are presented in this paper. The circular patch antennas electrical parameters on the human body were analyzed by using commercial full-wave software. The circular patch metamaterial wearable antennas are compact and flexible. The directivity and gain of the antennas with Circular Split-Ring Resonators (CSRR) is higher by 2.5dB to 3dB than the antennas without CSRR. The resonant frequency of the antennas without CSRR is higher by 6% to 9% than the antennas with CSRR. The computed and measured bandwidth of the stacked circular patch wearable antenna with CSRR for IoT and medical applications is around 12%, for S11 lover than −6dB. The gain of the circular patch wearable antenna with CSRR is around 8dBi.

Performance of a New Design Based on Substrate-Integrated Waveguide Slotted Antenna Arrays for Dual-Band Applications (Ku / K)

This paper introduces and discusses the study of a new concept for SIW array antenna development. This conducted development is based on three designs, two of them related to 1x2 arrays fed by SIW line, combined with SIW inset line, and the last designed for 2X2 array antenna feed by SIW inset line. All these structures are designed to give dual-band at (Ku - K) bands with enhanced gain and bandwidth. The new 2x2 array antenna has a high gain, and it consists of four SIW cavities staggered patches with a 90° phase shift, which are fed using microstrip line shielded by SIW vias. The designs were conducted using full-wave simulator ANSYS HFSS - the frequency domain solver. The 2x2 array antenna gives a return loss about (-20 dB), a high gain of 9.05 dB, and two bandwidth equals 210 MHz and 1310 MHz respectively at both of the operating bands. To validate the simulated results the simulation was conducted again using the time-domain solver of the CST Microwave Studio (MWS) full-wave simulator. Simulation results obtained from the two software having different solvers were in good agreement in the results.