Related papers: Spillover and diffraction sidelobe contamination i…
Dynamic modification of the pattern of a reflector antenna system traditionally requires an array of feeds. This paper presents an alternative approach in which the scattering from a fraction of the reflector around the rim is passively…
Accurate optical modeling is important for the design and characterisation of current and next-generation experiments studying the Cosmic Microwave Background (CMB). Geometrical Optics (GO) cannot model diffractive effects. In this work, we…
We have mapped the total sky brightness at 1465 MHz in two adjacent 60-degree declination bands with the portable 5.5-m parabolic reflector of the Galactic Emission Mapping (GEM) project, an on-going international collaboration to survey…
Telescopes measuring cosmic microwave background (CMB) polarization on large angular scales require exquisite control of systematic errors to ensure the fidelity of the cosmological results. In particular, far-sidelobe contamination from…
The performance of antennas can severely deteriorate in the presence of adjacent electrically-large scatterers. In this work, we use a conducting hollow cylinder to shield the scatterer. The cylinder is shelled with single layer dielectric…
We describe the development of two circularly symmetric antennas with high polarization purity and low spillover. Both were designed to be used in an all-sky polarization and intensity survey at 5 GHz (the C-Band All-Sky Survey, C-BASS).…
Mitigating the far sidelobes of a wide field-of-view telescope is one of the critical issues for polarization observation of the cosmic microwave background. Since even small reflections of stray light at the millimeter-wave absorbers…
This paper presents 73 GHz wideband outdoor foliage and ground reflection measurements. Propagation measurements were made with a 400 Megachip-per-second sliding correlator channel sounder, with rotatable 27 dBi (7 degrees half- power…
This paper provides an analysis of radio wave scattering for frequencies ranging from the microwave to the Terahertz band (e.g., 1 GHz - 1 THz), by studying the scattering power reradiated from various types of materials with different…
In this second part of a series we attempt to construct an empirical model that can mimick all experimental observations made regarding the role of an alternative interleaved scan pattern in STEM imaging on the beam damage in a specific…
Since the Galactic center is ~1000 times brighter than fluctuations in the Cosmic Microwave Background (CMB), CMB experiments must carefully account for stray Galactic pickup. We present the level of contamination due to sidelobes for 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…
This is the first part in a series of two papers that concern with the quantitative analysis of the electromagnetic field enhancement and anomalous diffraction by a periodic array of subwavelength slits. The scattering problem in the…
In this paper, we demonstrate a radiation-strength-chirped metasurface centimeter-long grating antenna, whose beam quality is approaching the diffraction limit in its footprint with 90 percent efficiency.Instead of chirping the duty cycle…
Diffraction gratings with high upward diffraction efficiency and large effective length are required for chip-scale light detection and ranging. In this paper, we propose a diffraction grating based on a multilayer silicon nitride…
Diffraction patterns of electrons are believed to resemble those of electromagnetic waves (EMW). I performed a series of experiments invoked to show that the periodicity of peaks in the diffraction diagram of electrons is concerned with the…
We present near-field radio holography measurements of the Simons Observatory Large Aperture Telescope Receiver optics. These measurements demonstrate that radio holography of complex millimeter-wave optical systems comprising cryogenic…
As opposed to metasurfaces, metagratings represent themselves sparse arrangements of scatterers. Established rigorous analytical models allow metagratings to overcome performance of metasurfaces in beam steering applications while handling…
Millimeter-wave wireless networks offer high throughput and can (ideally) prevent eavesdropping attacks using narrow, directional beams. Unfortunately, imperfections in physical hardware mean today's antenna arrays all exhibit side lobes,…
We experimentally study the dispersion relation of waves in a two-dimensional (2D) defect layer with periodic nanopores that sits on a three-dimensional (3D) photonic band gap crystal made from silicon by CMOS-compatible methods. The…