F. Rostan

Design and Performance of Conformal Microstrip Patch Arrays on Cylindrical Surfaces

Conformal microstrip patch arrays are used in many applications for mobile communications pertaining to satellites, spacecrafts and aircrafts. The paper shows the mathematical treatment of such conformal microstrip arrays using a spectral domain approach. The attainable radiation patterns with respect to the number of patches, the patch size, the cylinder diameter etc. are shown. Several possibilities for the practical realisation of microstrip patch arrays are discussed and the measured results for frequencies from 10.3 GHz up to 36.5 GHz are presented. Excellent agreement between calculated and measured results are achieved.

Design of aperture-coupled patch antenna arrays with multiple dielectric layers

Using inexpensive foam materials in the design of aperture-coupled patch antennas, large bandwidth and excellent cross polarisation properties can be achieved. This paper shows the mathematical treatment of such antennas using a spectral domain approach and the exact Greens functions for multiple dielectric layers. The performance of a 16 × 16 element array for 12.625 GHz will be demonstrated.

Conformal microstrip patch array for SDMA applications

This paper presents the calculated and measured space division multiple access (SDMA) performance of a conformal 16x4 element microstrip patch phased array on a cylindrical surface. The described pattern synthesis algorithm allows a fast and efficient evaluation of all the array excitation coefficients, which are necessary to generate the required beams for the SDMA operation of base stations. The array shows an excellent scanning and beam forming capability and is a very promising candidate for the SDMA operation of base stations for mobile communications and for point-to-multipoint connections.

Aperture-coupled microstrip patch phased arrays in C- and X-band: a contribution to future multi-polarization multi-frequency SAR systems

Future spaceborne SAR systems will use active phased array antennas with multi-polarization and multi-frequency capabilities. For high resolution SAR images of high quality the antennas have to provide a large bandwidth and an extreme polarization purity. These requirements can be met by aperture-coupled microstrip patch phased arrays based on low-permittivity, low-weight and low-cost foam substrates. The paper presents their design and their measured performance in C-band (5.3 GHz) and X-band (9.6 GHz).

Dual polarized L-band microstrip patch array for the AIRSAR/TOPSAR system

Describes the design and initial results of an advanced dual polarized 8x2 element microstrip patch array for the new NASA/JPL dual frequency C- and L-band interferometric SAR. The new dual polarized L-band antenna for the AIRSAR/TOPSAR system consists of aperture-coupled microstrip patch elements on a foam substrate, yielding a high polarization purity, low losses, a good port-to-port isolation and a large bandwidth.

Dual polarized multilayer aperture-coupled patch antennas for spaceborne application in C- and X-band

The paper discusses the element and subarray requirements and designs for advanced dual polarized future spaceborne SAR antennas using aperture-coupled microstrip patch elements. Special emphasis is given to achieve high polarization purity, low loss, good port-to-port isolation, high bandwidth and high aperture efficiency. Two design examples are shown for frequencies in C-band (5.3 GHz) and X-band (9.6 GHz) having a port-to-port-isolation of 25 dB and a polarization isolation better than 28 dB.<<ETX>>

Mutual coupling in aperture-coupled microstrip patch arrays with a sequential feeding technique

Aperture-coupled microstrip patch antennas are very attractive candidates for many polarimetric phased array applications. They offer an excellent electrical performance and are easy to manufacture. Due to their multilayer design an optimum choice can be made for the patch and the feed substrate. Low-permittivity patch substrates yield a high bandwidth as well as high radiation efficiency. Dual linear polarization can be achieved by either crossed slot or offset slot configurations. Depending on the bandwidth the typical polarization isolation of dual polarized aperture-coupled antenna elements on low-permittivity substrates is about -25 dB. However, for several phased array applications a even higher polarization isolation is required. By sequential feeding techniques a significant improvement of the polarization purity at the array level with values of better than -45 dB is achieved. However, microstrip patch arrays with sequentially rotated antenna elements show a different coupling and scan behavior than arrays with unidirectional aligned antenna elements. This paper investigates microstrip patch arrays for phased array applications in the C-band with a sequential feeding technique.

Dual polarized microstrip patch arrays for the next generation of spaceborne synthetic aperture radars

Discusses the requirements and the design of an advanced dual polarized future spaceborne SAR antenna using aperture-coupled microstrip patch elements. Special emphasis is given to achieve a high polarization purity, low loss, good port-to-port isolation and a high bandwidth. Results of a design study on an 8/spl times/1 element subarray as well as on an 8/spl times/8 element breadboard in C-band are presented.

Aperture-coupled microstrip patch phased arrays in C- and X-band : A contribution to future multi-polarization multi-frequency SAR systems

Future spaceborne SAR systems will use active phased array antennas with multi-polarization and multi-frequency capabilities. For high resolution SAR images of high quality the antennas have to provide a large bandwidth and an extreme polarization purity. These requirements can be met by aperture-coupled microstrip patch phased arrays based on low-permittivity, low-weight and low-cost foam substrates. The paper presents their design and their outstanding measured performance in C-band (5.3 GHz) and X-band (9.6 GHz). The constructed arrays show bandwidths of more than 150 MHz in C-band and more than 300 MHz in X-band. The polarization purity is typically in the range of 40 dB.

Wideband microstrip patch array with low sidelobes and a high polarisation purity for high resolution imagin radars

The design and the measured performance of a wideband microstrip patch array for a high resolution imaging radar is described. The array consists of aperture-coupled microstrip patch elements based on low-permittivity foam materials. The array is designed by a method of moments approach under consideration of mutual coupling effects. The manufactured 8×8 element cosine tapered X-band array shows a bandwidth of 1.8 GHz (VSWR<2), which is more than 18% of the centre frequency. Within this bandwidth the sidelobes remain below ¿20 dB. The cross-polarisation level is below ¿30 dB for all aspect angles and even below ¿38 dB for aspect angles between ±60°.