Przemyslaw Gorski

On omnidirectional coverage with minimum number of circularly polarized patch antennas placed on minisatellites

In the design of spacecraft, modern numerical electromagnetism can effectively deal with studies into optimization of antenna placement. Such studies are of great importance to reduce risks of disruption communication between spacecraft and ground stations (GS). We had carried out an extensive numerical modeling and experimental validation of the simulation results in this area. These efforts were concentrated on determination of a combined radiation pattern for several antennas mounted on minispacecraft. Size of a main body of the minispacecraft under analysis was up to ~60x60x70cm (23x23x27 inches). In the analysis we had drawn our attention to effects related to solar panels and we proposed technical means to mitigate impact of failed panel deployment to the communication subsystem.

The omnidirectional coverage of low-profile TTC antennas onboard minispacecraft

The optimization of antenna placement onboard minisatellites is key in shaping the coverage pattern of TTC (telemetry, teleranging and telecommand) links. A careful selection of phasing between two or more TTC antennas is needed to mitigate the occurrence of nulls and to maintain the directions of the majority of the radio wave propagation towards the Earth-facing side. In the case of a small spacecraft, the MoM offers acceptable computing time and accuracy.

Optimizing TT&C antenna placement on minisatellites

The paper presents results of our studies on electrical properties of microstrip antennas mounted on minisatellites. The main feature of minisatellite antennas is a lightweight structure and a high degree of integration of antenna elements and feeding circuits. The antennas onboard minisatellites is divided into two groups: telecommand/housekeeping telemetry antennas (TT&C) and payload antennas. The main objective of the research is the optimization of antenna placement onboard the minisatelliate.

Onto optimization of TTC patch antennas placed on minispacecraft

This paper presents the approach to optimal TTC patch antennas placement onboard minispacrafts. The construction of the antennas is briefly discussed and chosen schemes of antennas placement are introduced. Influence of solar panels is also investigated and countermeasures against failure of their deployment are proposed. The results of the analysis were obtained with the use of Moment Method simulations and measurements. Alternative, computationally more efficient ray-tracing method is mentioned and compared with full-wave simulations.

Low profile dual-polarized antenna array for operation at the K band

Gradual implementation of new services and new technologies at K-bands (i.e. 16-32 GHz), calls for major advancement in antenna array technology. Low-profile antenna are in particular desire. We present some results of investigations into antenna elements made for use in arrays. The main design objectives are antenna element capability to operate with a pair of orthogonal polarizations and low profile. The minimum bandwidth expressed in terms of not only impedance match, but with use of four other major antenna parameters is 1 GHz.

Highly Integrated Ligthweight Dual Band Antenna with Dual or Quadruple Polarization Agility

Wireless and mobile communication often calls for dual-band antenna modules. Presently, agility in polarization properties in such antennas is getting on a sense of urgency. The antennas desired by the industry should be manufactured in the lightweight technology supporting high degree of integration between antenna elements and microwave feeding circuits. The well suited approach is use of multilayer composite panels carrying at the bottom side microwave printed circuits needed to generate at least two polarizations. This paper presents the results of our research on dual-band antenna modules with an integrated compact microwave feeding network.

Omnidirectional Coverage Accomplished Onboard Small Spacecraft with the Use of Low-Profile Patch Antennas

This paper presents the methods of achieving an omnidirectional radiation pattern with the use of patch antennas mounted on minisatellites. Chosen simulation results are given for a few analyzed cases.

Low profile multilayer dual circular polarized K-band antenna array for aerospace applications

This paper, present results of studies and measurements on a dual circularly polarized 2×2 planar antenna array featuring a high degree of antenna circuit integration. The antenna has been designed with aerospace applications in mind. With a compact geometry and 20% bandwidth, this small array promises excellent performances and should enable many innovative applications in K-band, either standalone or as a building block of larger arrays.

Resonator structures on AlN ceramics surface treated by laser radiation

In this paper a method for producing resonant structures using laser micromachining is presented. In the spot of laser beam impact on AlN ceramics surface a conductive aluminum layer is formed. Compilation of process parameters allows for the fabrication of structures with resistance at Rs ~ 0.01Ω/Rs. It has been also found out that the maximum value of resistance for which spiral resonator structures manifest their unique properties is at the level of Rs = 1.43 Ω. Furthermore, the occurrence of mutual capacity which value is dependent on the arrangement of individual SR structures with respect to each other was observed and examined. Based on satisfactory results for SR structures, it has been attempted to produce a resonant structures dedicated to the THz range based on the process of direct metallization of AlN ceramics surface. As a result, the Split Ring Resonator structure whose properties were verified by using the THz -TDS method was manufactured. In case of the field E perpendicular to SRR structure and one resonance area for 0.50 THz with field E parallel to the structure, two characteristic resonant dips for 0.22 THz and 0.46 THz were obtained. The studies confirmed that the method of direct metallization of AlN ceramics allows to produce resonant structures in the THz range.

Spiral resonator manufactured on AlN ceramics to filter the coupled wave between patch antennas

The objective of this paper was to present an alternative technique of manufacturing the unit cells of spiral-shaped resonators (SR) on the aluminium nitride (AlN) ceramics. In this technique the AlN plane surface is irradiated by the Yb:glass medium-power laser (1.06 µm). As a result of the irradiation by a focused laser beam (a laser beam power up to 20 W), the rupture of the aluminium and nitrogen physical bonds occurs. Under such circumstances the conductive aluminium “paths” are formed on the originally insulating ceramic surface. Upon obtaining low ohmic conductive paths, this method makes for the feasible manufacturing of metamaterial structures. In carried out studies, the usage of such structures to suppress the coupling between pairs of patch antennas has been examined. The improvement of the mutual coupling at the level of 10 dB has been obtained. One of the advantages of the demonstrated method is a possibility to perform the selective and direct metallization of the AlN ceramics surface without using any mask as opposed to photolithography. It greatly reduces the implementation time of the projected metamaterial structures.