Broadband dual-band linear orthogonal polarisation reflectarray

A single-layer dual-band orthogonal polarisation reflectarray antenna composed of a combination of split cross and rectangle rings for one band and double split square rings for the other band is presented. Using these types of cell elements, a wideband, single-layer dualband (12 GHz/14 GHz) orthogonal polarisation reflectarray is designed, fabricated, and tested. Measured results demonstrate radiation efficiency close to 60% for both bands and a 1 dB gain bandwidth of 24% for the lower band and 19% for the upper band.     

Channel coupling in orthogonal polarisation diversity systems and its influence on diversity gain

The effects of channel coupling (CC) in two-branch orthogonal polarisation antenna diversity systems both on the correlation and the mean power difference between received signals are reported. It is shown that the presence of CC increases the correlation but probably decreases the mean power difference and hence improves the diversity gain.     

Investigation of the effects of precipitation on parabolic antennas employing linear orthogonal polarisation at 11 GHz

The results of an investigation on the effects of precipitation on the crosspolarisation discrimination attainable from parabolic antennas for orthogonal linearly polarised radio signals at 11 GHz are given. In particular, results of artificial wetting experiments on the dish and feed apertures are presented, together with a summary of the results from natural precipitation (including snow) on an antenna when used on a short test link.     

Meteor burst polarisation trials

Measurements over an 850 km path show that radio waves reflected by ionised meteor trails are typically received with the same polarisation as they were transmitted. Furthermore, a vertically polarised wave seems to suffer a 3?4 dB larger loss than a horizontally polarised one.     

All-fibre wideband polarisation beam-combiner

An all-fibre polarisation beam-combiner with more than 200 nm spectral width for -15 dB extinction ratio is demonstrated. The design is based on a narrowband polarisation beam-combiner coupler in association with a WDM coupler in a Mach-Zehnder interferometer structure.     

Backscattering for circular polarisation

Equations are given that express scattering for transmitting and receiving circularly polarised waves in terms of the characteristics for linear polarisation. Special cases are discussed, for which it is possible to estimate the radar cross-section for one polarisation based on data for other polarisations. Knowledge of polarisation characteristics is sometimes helpful for acquiring insight into the scattering mechanisms of complex surfaces.     

Monomode fibre polarisation scrambler

A technique for the pseudodepolarisation of a long-coherence-length source is described, which is based on a simple polarisation modulation scheme. Using a length of high-birefringence fibre wound on to a piezoelectric transducer, a simple all-fibre polarisation scrambler can be constructed.     

Uniaxial chiral quarter-wave polarisation transformer

The uniaxial chiral medium is a generalisation of the well-studied isotropic chiral media. It is obtained when microscopic helices with parallel axes are positioned in a host dielectric in random locations. Solutions for the dispersion equation and for the eigenwaves for a uniaxial chiral medium were recently found. Here the authors consider the polarisation properties of a transverse wave propagating through a uniaxial chiral slab. The results give a simple possibility for constructing a polarisation transformer for changing the polarisation of a propagating plane wave.<>     

All-single-mode-fibre interferometric polarisation beam splitter

A novel all-fibre polarisation beam splitter based on an all-fibre Mach-Zehnder interferometer (MZI) is reported. The device symmetrically separates orthogonally polarised components of an incoming optical signal with isolations between these components of greater than 17 dB at each output     

Lithium niobate waveguide polarisation convertor

A wavelength-insensitive, integrated-optic lithium niobate device capable of arbitrary polarisation transformations is described. Detailed investigation of the experimental performance shows excellent agreement with the theoretically predicted behaviour     

Rugged all-fibre endless polarisation controller

A polarisation controller comprising four lengths of PM fibre wound onto piezoelectric cylinders has been produced. It is mechanically rugged, has an insertion loss of 1.5 dB, and is capable of endless control between two arbitrary time-varying states of polarisation. Polarisation control has been successfully demonstrated for the first time in a coherent optical transmission system over installed fibre     

Polarisation-insensitive heterodyne detection using polarisation scrambling

Theoretical and experimental results are presented which demonstrate that polarisation diversity can be implemented by rapidly stepping the polarisation of an optical signal between orthogonal states prior to transmission through a birefringent medium.     

Helix antenna with optimised main-beam polarisation

A helical antenna with a high degree of polarisation purity for directions near endfire is described. The antenna structure was optimised by numerical analysis of its polarisation properties. Theoretical and experimental results are presented.     

Reconfigurable microstrip antenna with polarisation diversity

A single probe-fed reconfigurable microstrip patch antenna with symmetric cross slots is proposed. By controlling four pin diodes on the patch slots, the proposed antenna has right hand circular polarisation, left hand circular polarisation or linear polarisation.     

High performance polarisation splitting fibre coupler

Presents an original design of a polarisation splitting coupler based on stress release in polished birefringent single-mode fibres within orthogonal orientation. 1.55 μm was used for coherent telecommunication applications and the best result was 25 dB of selectivity     

All-optical polarisation differential amplification withbirefringent fibre

The authors propose and experimentally demonstrate that all-optical amplification of small polarisation changes may be achieved at relatively low powers by using a multibeatlength nonlinear polarisation coupler