相关论文: Implementation of an Optimised Cassegrain System f…
Interferometric millimeter observations of the cosmic microwave background and clusters of galaxies with arcmin resolutions require antenna arrays with short spacings. Having all antennas co-mounted on a single steerable platform sets…
Cassegrain designs can be used to build thin lenses. We analyze the relationships between system thickness and aperture sizes of the two mirrors as well as FoV size. Our analysis shows that decrease in lens thickness imposes tight…
We describe an upgrade to the Cosmic Background Imager instrument to increase its surface brightness sensitivity at small angular scales. The upgrade consisted of replacing the thirteen 0.9-m antennas with 1.4-m antennas incorporating a…
We present two novel designs for a telescope suitable for massively-multiplexed spectroscopy. The first is a very wide field Cassegrain telescope optimised for fibre feeding. It provides a Field Of View (FOV) of 2.5 degrees diameter with a…
FAST, the largest single-dish radio telescope in the world, has a 500-meter diameter main reflector and a 300-meter diameter illumination area. It has a shape variable main reflector, which changes the shape of the illuminated area in the…
The model of the reflector antenna system with focal plane array, low-noise amplifier and beamformer is developed in the work. The beamformer strategy is suggested to reduce the receiving sensitivity ripple inside field of view of the…
The Arcminute Microkelvin Imager (AMI) is a telescope specifically designed for high sensitivity measurements of low-surface-brightness features at cm-wavelength and has unique, important capabilities. It consists of two interferometer…
The Arcminute Microkelvin Imager is a pair of interferometer arrays operating with six frequency channels spanning 13.9-18.2 GHz, with very high sensitivity to angular scales 30''-10'. The telescope is aimed principally at…
Curved reflective mirrors play an indispensable role in widely-employed Cassegrain-type optics, which consequently are inevitably bulky, and thus neither integratable nor well extendable. Through substituting geometric phase based…
Over the last few years a number of software and hardware improvements have been implemented to the 32-m Cassegrain radio telescope located near Toru\'n. The 19-bit angle encoders have been upgraded to 29-bit in azimuth and elevation axes.…
Radio telescopes are susceptible to interference arriving through its sidelobes. If a reflector antenna could be retrofitted with an adaptive null steering system, it could potentially mitigate this interference. The design of a…
The Low Frequency Instrument on board the ESA Planck satellite is coupled to the Planck 1.5 meter off-axis dual reflector telescope by an array of 27 corrugated feed horns operating at 30, 44, 70, and 100 GHz. We briefly present here a…
The emerging technology of large (~ 10,000 pixel) submillimeter-wave bolometer arrays presents a novel optical design problem---how can such arrays be fed by diffraction-limited telescope optics where the primary mirror is less than 100,000…
We have designed and developed a compact ultraviolet imaging payload to fly on a range of possible platforms such as high altitude balloon experiments, cubesats, space missions, etc. The primary science goals are to study the bright UV…
Application of reflector antenna configurations in designing the optical section of terahertz imaging systems has attracted great attention during recent years. Advantages of reflective optics in comparison with refractive optics is one of…
The miniaturisation of optical systems is an ongoing challenge across the electromagnetic spectrum. While the thickness of optical elements themselves can be reduced using advances in metamaterials, it is the voids between these elements --…
A new method based on parameters iteration technique has been developed to determine the optimal subreflector position for shaped Cassegrain antennas to improve the electromagnetic (EM) performance distorted by gravity. Both the features of…
In the past two decades, a rebirth of interest in low-frequency radio astronomy for 21 cm tomography of the Epoch of Reionization, has given rise to a new class of radio interferometers with $N \gg 100$ antennas. The availability of…
The design of an improved microstrip antenna operating in the 28 GHz frequency spectrum is the main goal of this work. The design used a Roger RT 5880 LZ substrate with a thickness and permittivity of 0.762mm and 1.96, respectively. The…
This paper describes the design of a 5.5:1 bandwidth feed antenna and reflector system, intended for use in hydrogen intensity mapping experiments. The system is optimized to reduce systematic effects that can arise in these experiments…