Andreas Ericsson

Design and Analysis of a Multilayer Meander Line Circular Polarization Selective Structure

We present a nonresonant circular polarization selective structure (CPSS) based on multiple layers of stacked meander line sheets arranged closely after each other. The structure has a total thickness of 13.5 mm (0.68 wavelengths at center frequency 15 GHz) and is realized by cascading printed circuit boards interspaced with a low-permittivity foam material, and the different layers are bonded together with thin layers of adhesive spray. A design procedure is presented that can be used to optimize the proposed structure based on its target band of operation. Based on this method, an optimized design has been simulated, and the structure shows a return loss and an insertion loss better than 0.5 dB, and axial ratio in transmission and reflection better than 0.78 dB, over a fractional bandwidth of 45.8% at normal incidence, fully covering the Ku-band 12–18 GHz. The functionality of the structure has been verified experimentally through measurements, both in reflection and transmission, with a total bandwidth of 42.0%, covering 86.7% of the Ku band. The simulated performance at oblique angles of incidence shows significant improvements when compared to classical resonant CPSSs.

A resonant circular polarization selective structure of closely spaced wire helices

A circular polarization selective structure (CPSS) reflects one handedness of circular polarization and transmits the other. We present a resonant CPSS structure consisting of closely spaced Morin helices. Simulation results demonstrate that the design can operate over ±20° angle of incidence variation and has a bandwidth of about 10% at normal incidence. A suggested design case is presented, where the CPSS is implemented in a shared aperture circular polarization offset reflector antenna for satellite communication in the Ku-band uplink of Australia at 17.3 GHz <; f <; 18.1 GHz.

A resonant circular polarization selective structure of closely spaced Morin helices

A circular polarization selective structure (CPSS) reflects one handedness of circular polarization and transmits the other. We present a resonant CPSS structure consisting of closely spaced Morin helices. Simulation results demonstrate that the design can operate over ±20° angle of incidence variation and has a bandwidth of about 10% at normal incidence. A suggested design case is presented, where the CPSS is implemented in a shared aperture circular polarization offset reflector antenna for satellite communication in the K u -band uplink of Australia at 17.3 GHz < f < 18.1 GHz.

Experimental Characterization of Circular Polarization Selective Structures Using Linearly Single-Polarized Antennas

We present a technique for performing high-accuracy measurements of the transmission and reflection properties in circular polarizations (CPs) of a test panel. Using linearly polarized antennas and measuring at four different antenna orientations, all with a relative rotation of 45°, an efficient normalization of each scattering component can be utilized. This method achieves a high signal-to-noise ratio in all normalized linear polarization components used to synthesize the CP scattering. Furthermore, a postprocessing scheme is introduced to compensate for measurement uncertainties due to antenna misalignments. The novel measurement and postprocessing techniques are utilized to characterize a manufactured wideband CP selective structure, both in transmission and reflection, and the measurement results are in excellent agreement with simulation results from commercial software. The repeatability of the measurement results is investigated, and the results are in the expected range in comparison with estimated measurement uncertainties.

A homogenization procedure for microstructured resistive sheets

A thin resistive sheet is described by its sheet conductance, and the electric and magnetic dipole moments per unit area. All three properties can be controlled by the material parameters and geometry of the sheet, for instance by making a periodic pattern of holes in it. A mathematical analysis of the low frequency limit of Maxwells equations in a periodic setting generates a hierarchy of local problems which can be used to compute the conductance and electric and magnetic polarizability per unit area of the microstructured sheet. We present results from a numerical implementation of these local problems, and discuss the region of validity for the asymptotic solution.

Compressive Sensing Techniques for mm-Wave Nondestructive Testing of Composite Panels

This paper presents imaging results from measurements of an industrially manufactured composite test panel, utilizing two introduced algorithms for data postprocessing. The system employs a planar near-field scanning setup for characterizing defects in composite panels in the 50–67-GHz band, and can be considered as a complementary diagnostic tool for nondestructive testing purposes. The introduced algorithms are based on the reconstruction of the illuminating source at the transmitter, enabling a separation of the sampled signal with respect to the location of its potential sources, the scatterers within the device under test or the transmitter. For the second algorithm, an

60 GHz imaging of panels for defect detection using planar scanning

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Quasi periodicity in moiré patterns and a numerical approximation method of dual weaves

-minimization problem formulation is introduced that enables compressive sensing techniques to be adapted for image retrieval. The algorithms are benchmarked against a more conventional imaging technique, based on the Fourier transform, and it is seen that the complete imaging system provides increased dynamic range, improved resolution, and reduced measurement time by removal of a reference measurement. Moreover, the system provides stable image quality over a range of frequencies.

A multi layer meander line circular polarization selective structure (MLML-CPSS)

This paper presents imaging results of measurements conducted at 60 GHz, using the planar rectangular near-field technique. Utilizing the stated techniques at higher frequencies enables detection of smaller defects, and allows for a small measurement set-up in a laboratory environment. An algorithm based on the Fast Fourier Transform (FFT) has been developed in order to process the data. The paper provides measurement results for an illustrative panel, which show clear detection of the distributed defects. The purpose of this work is to enable processing of recent data from measurements of industrial composite panels.

A performance study of circular polarization selective structures

This work describes a method to compute the periodicity and the relative hole area of a dual weave arrangement where the weaves are rotated relative to each other. Due to the discovery of 2D quasi periodicity in these dual weaves, a method developed to approximate the macroscopic behaviour of the dual weave is introduced. These methods are useful when designing dual weave reflector antenna surfaces for satellite communication applications.