The STRIP instrument of the Large Scale Polarization Explorer: microwave eyes to map the Galactic polarized foregrounds

In this paper we discuss the latest developments of the STRIP instrument of the "Large Scale Polarization Explorer" (LSPE) experiment. LSPE is a novel project that combines ground-based (STRIP) and balloon-borne (SWIPE) polarization measurements of the microwave sky on large angular scales to attempt a detection of the "B-modes" of the Cosmic Microwave Background polarization. STRIP will observe approximately 25% of the Northern sky from the "Observatorio del Teide" in Tenerife, using an array of forty-nine coherent polarimeters at 43 GHz, coupled to a 1.5 m fully rotating crossed-Dragone telescope. A second frequency channel with six-elements at 95 GHz will be exploited as an atmospheric monitor. At present, most of the hardware of the STRIP instrument has been developed and tested at sub-system level. System-level characterization, starting in July 2018, will lead STRIP to be shipped and installed at the observation site within the end of the year. The on-site verification and calibration of the whole instrument will prepare STRIP for a 2-years campaign for the observation of the CMB polarization.Comment: 17 pages, 15 figures, proceedings of the SPIE Astronomical Telescopes + Instrumentation conference "Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX", on June 15th, 2018, Austin (TX

Analysis and design of passive waveguide devices by spectral element methods

This work will present a spectral-element method suitable for the efficient design of two-dimensional passive waveguide components. The method exploits different domain mappings in order to correctly model the singular behavior of the field close to sharp edges also in presence of curved sides. Several devices for satellite communication and scientific instrumentation have successfully been designed with the present technique. Detailed comparison between simulated and measured performances will prove the reliability of the method also when very demanding specifications are set on components desig

Synthesis Strategy for Broadband Multiplexers

This paper presents a design method for wideband multiplexers. It is based on an aggregate discontinuity concept to keep the mutual loading effect of the various filters into account at the synthesis level. This method can provide the geometric parameters of the multiplexer starting from the desired polynomial frequency response. The obtained performance of a designed waveguide diplexer with a 1.4% separation bandwidth is discusse

W-Band Orthomode Transducer for Dense Focal-Plane Clusters

A W-band orthomode transducer has been designed for polarimeter clusters in dense focal planes. Its compact geometry, with aligned output ports, allows for a closely-spaced triangular-lattice arrangement. At these high frequencies, the platelet manufacturing strategy has been applied and verified experimentally on seven prototypes, showing reflection coefficients lower than polarimeter clusters-20 dB, insertion loss of about 0.25 dB and cross-coupling and isolation levels of -42 dB and 45 dB, respectively, in a 30% bandwidt

Analysis and design of passive waveguide devices by spectral element methods

This work will present a spectral-element method suitable for the efficient design of two-dimensional passive waveguide components. The method exploits different domain mappings in order to correctly model the singular behavior of the field close to sharp edges also in presence of curved sides. Several devices for satellite communication and scientific instrumentation have successfully been designed with the present technique. Detailed comparison between simulated and measured performances will prove the reliability of the method also when very demanding specifications are set on components desig

Synthesis Strategy for Broadband Multiplexers

This paper presents a design method for wideband multiplexers. It is based on an aggregate discontinuity concept to keep the mutual loading effect of the various filters into account at the synthesis level. This method can provide the geometric parameters of the multiplexer starting from the desired polynomial frequency response. The obtained performance of a designed waveguide diplexer with a 1.4% separation bandwidth is discussed

Design considerations for a low-frequency Vivaldi array element

A cavity-backed Vivaldi antenna is suggested as dual-polarization array element for the low-frequency instrument of the Square Kilometer Array (SKA) project. A design strategy aimed at maximizing the sensitivity for such an array element is described. As an example, an antenna was obtained, with a sensitivity higher than 10 cm^2/K in the operative bandwidth and in the 45° sky coverage angle, for each polarization

Sardinia Aperture Array Demonstrator

We present a project aimed at realizing an Italian aperture array demonstrator constituted by prototypical Vivaldi antennas designed to operate at radio frequencies below 500 MHz. We focus on an array composed of a core plus a few satellite phased-array stations to be installed at the Sardinia Radio Telescope (SRT) site. The antenna elements are mobile and thus it will be possible to investigate the performance in terms of both uv-coverage and synthesized resolution resulting from different configurations of the arra