Feed horn

About: Feed horn is a research topic. Over the lifetime, 2395 publications have been published within this topic receiving 26548 citations. The topic is also known as: feedhorn.

A 700 GHz unilateral finline SIS mixer fed by a multi-flare angle smooth-walled horn

Abstract: We present the design of a broadband superconductor-insulator-superconductor (SIS) mixer operating near 700 GHz. A key feature of our design is the utilisation of a new type of waveguide to planar circuit transition comprising a unilateral finline taper. This transition is markedly easier to design, simulate and fabricate than the antipodal finline we employed previously. The finline taper and the superconducting circuitry are deposited on a 15 μm thick silicon substrate. The employment of the very thin substrate, achieved using Silicon-On-Insulator (SOI) technology, makes it easy to match the incoming signal to the loaded waveguide. The lightweight mixer chip is held in the E-plane of the waveguide using gold beam leads, avoiding the need for deep grooves in the waveguide wall. This new design yields a significantly shorter chip, free of serrations and a wider RF bandwidth. Since tuning and all other circuits are integrated on the mixer chip, the mixer block is extremely simple, comprising a feed horn and a waveguide section without any complicated mechanical features. We employ a new type of smooth-walled horn which exhibits excellent beam circularity and low cross polarisation, comparable to the conventional corrugated horn, and yet is easier to fabricate. The horn is machined by standard milling with a drill tool shaped into the horn profile. In this paper, we describe the detailed design of the mixer chip including electromagnetic simulations, and the mixer performance obtained with SuperMix simulations. We also present the preliminary measurements of the smooth-walled horn radiation patterns near the mixer operating frequencies.

Combined radar altimeter, radiometer sensor employing multiport feed horn having blended sidewall geometry

Abstract: A remote sensing apparatus for conducting (spaceborne) measurements of ocean geophysical parameters integrates a radar altimeter subsystem with a radiometer subsystem through the use of a shared antenna feed horn that permits each subsystem to have the same viewing aperture, so that each subsystem sees the same location on the ocean. The horn is a multiport, multifrequency horn having a throat and a tapered sidewall portion extending from the throat to the outer edge of the horn. A first sidewall port is coupled to the transmit/receive channel of the radar altimeter. A second sidewall port is coupled to a first receive channel of the radiometer, and a third sidewall port is coupled to a second receive channel of the radiometer. A throat port is coupled to a third receive channel of the radiometer. The tapered sidewall portion has a first, generally linear shape adjacent to the throat, a second, conic (elliptical) shape at its outer edge, and a third, blending shape disposed between and joining together the generally linear shape and the conic shape at the outer edge. The blending shape is preferably a sinusoidal function and serves to blend the first shape into the second shape in such a manner that the horn presents, over the entirely of the surface of the sidewall portion, an effectively continuous surface to the E plane of an electromagnetic wave emitted or received by the horn. The distance over which the sidewall portion is tapered to effect the blending function is preferably no greater than two wavelengths of the lowest frequency of electromagnetic waves emitted or received by the horn.

Electromagnetic Design of Feedhorn-Coupled Transition-Edge Sensors for Cosmic Microwave Background Polarimetry

Abstract: Observations of the cosmic microwave background (CMB) provide a powerful tool for probing the evolution of the early universe. Specifically, precision measurement of the polarization of the CMB enables a direct test for cosmic inflation. A key technological element on the path to the measurement of this faint signal is the capability to produce large format arrays of background-limited detectors. We describe the electromagnetic design of feedhorn-coupled, TES-based sensors. Each linear orthogonal polarization from the feed horn is coupled to a superconducting microstrip line via a symmetric planar orthomode transducer (OMT). The symmetric OMT design allows for highly-symmetric beams with low cross-polarization over a wide bandwidth. In addition, this architecture enables a single microstrip filter to define the passband for each polarization. Care has been taken in the design to eliminate stray coupling paths to the absorbers. These detectors will be fielded in the Cosmology Large Angular Scale Surveyor (CLASS).

A Practical Approach to Locate Offset Reflector Focal Point and Antenna Misalignment Using Vectorial Representation of Far-Field Radiation Patterns

Abstract: A direct and unambiguous approach to determine the focal point of a single offset reflector is presented. The proposed approach makes use of the vectorial form of far-field radiation patterns, both amplitude and phase. The method is based on iteratively defocusing the primary feed laterally and axially. First, mathematical expressions of the offset reflector with a small lateral and axial defocused feed are reviewed. Then, the numerical results are presented. It is shown how the corresponding far-field phase pattern information can be utilized to optimally locate the focal point of an offset parabolic reflector. The method can also be used to place the phase center of an unknown feed on the reflector focal point, and align the reflector on a test tower.

Coaxial Feed Pyramidal Horn Antenna with High Efficiency

Abstract: In this paper, a short pyramidal horn antenna with coaxial feed has been designed and fabricated with 52% bandwidth, which covers CDMA and GSM 900 bands. The total length of the antenna including c...