Antenski nizovi valovodnih otvor-antena i konverteri polarizacije izvedeni s pomoću planarnih laminata

This paper reviews not only the characteristic of the linearly-polarized plate-laminated waveguide slot array antenna in the 60 GHz band but also conversion to circular or tilted linear polarization by adding a layer of apertures over the antenna. The linearly-polarized antenna achieves about 80% antenna efficiency and more than 32 dBi of gain is achieved over 4.8 GHz bandwidth. The measured cross-polarization level is well suppressed below −45 dB in the boresite even though the slots are wide. The circularly-polarized 16×16-element array antenna achieves the axial ratio less than 3 dB over 2.5 GHz bandwidth. In the tilted linearly polarized 16 × 16-element array antenna, the measured cross polarization is below −30 dB in the boreside over approximately 5 GHz bandwidth.U ovom se radu razmatraju ne samo karakteristike linearno polariziranih antenskih nizova valovodnih otvor-antena, izvedenih s pomoću planarnih laminata, već i konverteri u kružnu odnosno kosu linearnu polarizaciju dobiveni dodavanjem sloja otvora iznad antene. Za linearno polariziranu antenu postignuta je efikasnost od oko 80% i dobitak veći od 32 dBi u frevencijskom pojasu širine 4.8 GHz. Izmjerena križna polarizacija manja je od −45 dB u smjeru glavne latice iako su rabljeni antenski otvori bili poprilično široki. Za kružno polarizirani antenski niz sa 16 × 16 elemenata postignuti je aksijalni odnos manji od 3 dB u frekvencijskom pojasu širine 2.5 GHz. U antenskom nizu s kosom linearnom polarizacijom sa 16 × 16 elementa izmjerena jakost križne polarizacije manja je od −30 dB u smjeru glavne latice u frekvencijskom pojasu širine 5 GHz

Low Cost SAR Antenna with Wide Swath and High Ground Resolution

This paper describes our developments of SAR (Synthetic Aperture Radar) antennas for low-cost, wide swath and high ground resolution (0.5-0.25m). The antennas are 1D deployable, plane slot array antennas with a wide elevation beam pattern. RF is fed to each panel with a novel patented technology, non-contact waveguide system between panels. These types of SAR antennas make feasible a newly proposed DiskSat with SAR sensor system. The SAR antenna 600MHz bandwidth in X band for 0.5m SAR resolution is made from carbon fiber reinforced plastic (CFRP) for light weight and thermal stability. Furthermore, range resolution improves with wider frequency bandwidth. Our novel technology, corporate feed slot array antenna is applied to the SAR antenna in X band with 1200MHz bandwidth aiming at 0.25m range resolution. Also, for a higher azimuth resolution, a sliding-spotlight SAR observation mode is effective. Then a wide area (20kmx20km) SAR observation with high resolution (0.25m) is briefly discussed

Control of phase in radial line slot antenna for 5G communications at 60GHz

This paper shows the design of a radial line slot antenna for being used in indoor environments in the 60 GHz band of the future 5G communication systems. The antenna is designed to work in near field situation, creating a uniform field in a certain volume, improving the size of this volume with respect the use of uniform phase. The paper analyzes different configurations of phase on the slots and performs the design of the slot position and length on the upper plate of the radial line slot antenna

Millimeter-wave multiplexed wideband wireless link using rectangular-coordinate orthogonal multiplexing (ROM) antennas

This paper is the first demonstration of multiplexed wideband data transmission in the millimeter-wave range using rectangular-coordinate orthogonal multiplexing (ROM) antennas. This spatial wireless multiplex communication method can be applied at several hundred GHz for further improvements in the data rate because much wider bandwidth is available and this multiplexing method does not require any signal processing. The multiplexing is achieved through the spatial eigenmodes of a novel antenna based on a rectangular coordinate system and magic-T which eliminates the need for computational signal processing efforts. The aperture distributions of these spatial eigenmodes are designed to have different polarities to avoid crosstalk and operate over a wide bandwidth range. We demonstrate their performance with four eigenmodes, achieving crosstalk between modes below -37.8 dB over a 14.6% relative bandwidth (57-66 GHz). We have introduced these antennas on a photonics-enabled real-time wireless data transmission, transmitting over two channels simultaneously, without any signal processing at the transmitter (multiplex) or the receiver (demultiplex). The two multiplexed channels show a total data rate up to 9.0 Gbps at most (5.875 Gbps and 3.125 Gbps for each channel) limited by the bandwidth of the low noise amplifiers at the receiver. The measured bit error rate (BER) is below the forward error correction (FEC) limit.This work was supported in part by SEI Group CSR Foundation and the Murata Science Foundation

Fabrication of Alternating-Phase Fed Single-Layer Slotted Waveguide Arrays using Plastic Materials with Metal-Plating

Abstract Lightweight single-layer slotted waveguide array antennas are fabricated using plastic materials with metal-plating. A plastic material that has good heat-radiation properties is investigated. Three types of antennas are fabricated in milling process, using ABS resin, heatradiating plastic, and aluminium alloy. In measurements, all three types of antennas are confirmed to have almost the same VSWR and gain around 25GHz frequency band

Study of the II Network as the Compound Slot Equivalent Circuit Model

A combination of Method of Moments (MoM) and compound slot Equivalent Circuit Model for linear array design is presented in this document. From the S Matrix of the single element, the more suitable network for its characterization is analyzed and selected. Then according to the radiation requirements of the desired array, the elements are designed and then properly connected by means of Forward Matching Procedure (FMP), which takes into account impedance matters in order to keep the input matched at the designing frequency. Comparison between HFSS simulations and MoM-FMP results are also presented. First part of this work was introduced in (1)(2) but a summary is included here to make the understanding easier

Technical Challenges for Small SAR Satellites with High Performance

We have developed a small SAR sensor, Micro X-SAR, compatible with 130 kg small satellite. It is capable of 3-meter resolution SAR image acquisition in strip-map mode and 1-meter resolution SAR image acquisition in sliding spotlight mode. This small SAR sensor was successfully demonstrated in orbit by a private company in 2021, Feb. This paper describes the next technical challenge of small SAR satellite with higher performance. We discuss on several types of SAR mission such as high resolution missions, wide swath missions, and constellation missions. Then we describe the present status of technical challenges to wideband, high power, and mass-productivity

Diseño de Arrays de Ranuras Compuestas Mediante Circuito Equivalente

Results of the methodology presented in [1] is shown in this document. By means of the equivalent circuit model [2][3] of the slot, a combination of Method of Moments (MoM) and Forward Matching Procedure (FMP) is used to design a sub-array of compound slots. According to this, the system can be seen as a matched electric circuit and/or as a Nelements radiating device. Comparison between commercial solvers and proposed method are shown in this document, revealing that the mutual coupling between elements is a tiltingangle-dependant parameter

Moment method analysis of parallel plate slot antennas

The authors propose a moment method analysis for the analysis of a parallel plate slot array, excited by a feed waveguide, based on the Flocket's theorem. The beam tilt of the incident wave, due to the frequency dependence of the excitation wavelength, is considered by using a complex Hertzian potential and periodic boundary conditions. A phase shift, that depends on the frequency, is included in the periodic conditions. This analysis can also be used for beam scanning arrays