This paper presents an element of a 2×2-element array antenna for Inmarsat BGAN/GPS applications. The element is an axial mode printed quadrifilar helical antenna that has been integrated with a compact feed network to provide sequential phase rotation for circular polarization (CP) radiation. The novel integrated lumped-element feed network is designed to provide a balanced RF power to the fou...

We present a systematic study of the circular polarization in pulsar integrated profiles, based on published polarization data. For core components, we find no significant correlation between the sense-change of circular polarization and the sense of linear position angle variation. Circular polarization is not restricted to core components and, in some cases, reversals of circular polarization...

Context. We investigate non-Zeeman circular polarization and linear polarization levels of up to 1% of 12CO spectral line emission detected in a shocked molecular clump around the supernova remnant (SNR) IC 443, with the goal of understanding the magnetic field structure in this source. Aims. We examine our polarization results to confirm that the circular polarization signal in CO lines is cau...

We report first-epoch circular polarization results for 133 active galactic nuclei in the MOJAVE program to monitor the structure and polarization of a flux limited sample of extra-galactic radio jets with the VLBA at 15 GHz. We found strong circular polarization (≥ 0.3%) in approximately 15% of our sample. The circular polarization was usually associated with jet cores; however, we did find a ...

We report first-epoch circular polarization results for 133 active galactic nuclei in theMOJAVE program tomonitor the structure and polarization of a flux-limited sample of extragalactic radio jets with the VLBA at 15 GHz.We found strong circular polarization ( 0.3%) in approximately 15% of our sample. The circular polarization was usually associated with jet cores; however, we did find a few s...

We present circular polarization results from a 5 GHz survey of the parsec-scale polarization properties of 40 AGN made with the VLBA. We find 11 circular polarization detections at the 3σ level or higher. This nearly quadruples the number of sources detected in circular polarization at VLBI resolution. We find no correlation between fractional linear and circular polarization across our sample...

We present multi-frequency, high resolution VLBA circular polarization images of the radio source 3C 84 in the center of NGC 1275. Our images reveal a complex distribution of circular polarization in the inner parsec of the radio jet, with local levels exceeding 3% polarization, the highest yet detected with VLBI techniques. The circular polarization changes sign along the jet, making 3C 84 als...

We present the first results of a circular polarization survey conducted with the Australia Telescope Compact Array (ATCA). We demonstrate the ability to make circular polarization measurements with a standard error of only 0.01 per cent, and have detections from both blazar and non-blazar active galactic nuclei (AGN). Our results show that, as a group, BL Lac sources and quasars have systemati...

We update the systematic studies of circular polarization in integrated pulse profiles by Han et al (1998). Data of circular polarization profiles are compiled. Sense reversals can occur in core or cone components, or near the intersection between components. The correlation between the sense of circular polarization and the sense of position angle variation for conal-double pulsars is confirme...

We describe recent results for Sgr A*, M81* and other low luminosity active galactic nuclei. We have conducted linear and circular polarimetry over a frequency range of 1.4 to 230 GHz and detected a variety of phenomena. The polarization properties of the studied sources are substantially different from higher powered AGN. In the case of Sgr A*, we are able to eliminate ADAFs and Bondi-Hoyle fl...