Tomasz Maleszka

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.

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.

Lightweight L and S-band antenna fed by three-strip directional couplers

Printed patch element are attractive from the electromagnetic point of view, however, their practical use often calls for involvement of layered composite panels. With such approach, patch elements can sustain mechanical loads or be integrated with antenna array carrying platforms. Owing to a lightweight multilayer structure with a thin substrate atop the thick one, the three-strip couplers put a lot of comfort in design of such antenna arrays. Wideband operation and low losses attract further attention to this coupler type as a good candidate for uses in antenna arrays. Dimensioning of the couplers are convenient for practical utilization in lower microwave bands. Furthermore, three-strip couplers make possible switching signals between printed circuit layers.

Lightweight conformal dual band antenna for spaceborne applications

The paper presents a dual-band integrated antenna for use onboard spacecraft. The L- and S-band antenna was developed in a course of our research we have carried on spacecraft antennas. The designed antenna features low profile which is more and more often desired in modern spacecraft. However, when antennas have low profile it is extremely difficult to generate high quality circular polarization over the wide spatial angle across the beam of the antenna element. The design of antenna electromagnetic and microwave circuits are meeting this expectation, so one patch is capable to serve well communication subsystem in one band across the entire radio horizon seen from the International Space Station (about 4000 km in diameter). Owing to conformality in the profile the antenna can be mounted on Earth and save significant efforts during attachment of the module.

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.

Investigations into patch elements developed for use in inflatable antenna arrays

There are vast demands for easily transportable and deployable antennas. Limits of weight minimization approach antennas made with thin dielectric films carrying printed circuits. Particularly when geometry of the support structure is stiffen with pressurized gas (similar as balloons) the ratio of the antenna size to its weight reaches extremely favorable values. Such electromagnetic structures may adopt majority of known antenna concepts, however, among most important are reflector and array antennas [1], [2]. Another interesting approach uses wave guiding structures between conductive surfaces. In this paper we concentrated on quasi-planar and cylindrical patch antennas. Our interest is in frequencies between 400 and 3000 MHz. For the actual structures of quasi-planar inflatable antennas a major technical constraint is the unavoidable geometrical deformations of the pressurized objects - main concerns are the deformations of element surfaces, especially the microstrip patches and feeding networks .

On combine radiation properties of patch antenna cluster placed on small boxes

Technology of manufacturing thin antennas in a form of multilayer patches, combining their feed circuits, is becoming mature enough to be used in many new applications. Use of such antennas is particularly favourable, when the antennas are mounted directly on walls of objects on which antennas are supposed to be carried (mainly vehicles and spacecraft). Among most important shapes are boxes made of conductive walls. In our studies, we investigated different concepts of patch antenna placement on such boxes. Numerical analysis was run with full- wave methods and with the geometrical Ray-tracing method. Results of simulations were compared to experimental results.

Integrated Inflatable Patch Antennas for Planar and Cylindrical Antenna Arrays

When rigidized with pressurized gas in a similar way as balloons, dielectric films carrying printed circuits can be considered for use as antennas. When the antenna is stiffen with pressurized gas, a ratio of the antenna size to weight, reaches maximum permissible values for the state-of-the-art material technologies. Furthermore, inflated patches are particularly attractive for wide potential uses, when they combine into arrays. This paper is focused on such lightweight printed antennas. Two forms of antenna elements and some recent our ideas for their beamforming circuits - made with thin films - are presented. To widespread uses, convenient antenna stowing and deploying is of great importance. That is why, it is recommended to develop feed networks with similar lightweight properties in a form of inflated cells. Generally, inflated antennas feature convex surfaces. For that reason they are well suited for use in conformal antennas, particularly in cylindrical ones.