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In this manuscript, the use of dielectric rod waveguide antenna (DRW) with an embedded planar lens is proposed as a highly directional alternative to an electrically large hyper-hemispheric silicon lens for emission at millimeter and sub-millimeter wave frequencies. DRW antennas radiate properly if only the fundamental mode is excited to the structure. Since photomixer-based terahertz sources excite...
In this paper, the coupling mechanism of a free-space Gaussian beam into a whispering-gallery mode resonator through a dielectric lens is mathematically modeled and numerically solved by means of the Schelkunoff-Waterman method (the so called T-matrix method). This approach allows in principle, to quickly analyze the performance of different near-field coupling mechanisms with arbitrary excitations...
This paper presents the design of an updated version of the dual polarized ultra wideband feed system for covering the new VGOS (VLBI Global Observation System). This feed system is based on an array version of four elements of the self-complementary conical log spiral antennas. The feed system achieves the VGOS's requirements with operating with high efficiency (> 50%) in a wide bandwidth from...
In this paper, an analytical framework is developed to study the performance of a planar-interface near-field coupler into a whispering gallery mode (WGM) resonator. We focus on the efficient coupling of a Gaussian beam under total internal reflection (TIR) at the planar interface of a lens, which is near a spherical resonator. The aim is to optimize the coupling in WGM nonlinear resonators, for high-sensitivity...
In this paper, a scheme for coupling free-space THz radiation into a nonlinear whispering-gallery mode (WGM) resonator is presented. The purpose is to detect the weak THz radiation from the cosmic microwave background (CMB) by up-converting the signal into the optical domain via the nonlinearity of the medium. Such high-sensitivity receiver has theoretically shown capabilities towards photon counting...
This manuscript proposes a high-power terahertz source that consists on a large amount of coherently driven photomixing THz sources. Each element is placed in the gap of a bow tie antenna. The resulting array defines a chessboard-like layout which maximize the density of devices. This novel concept is validated through full-wave simulations. Experimental considerations are also provided for a prototype...
This manuscript proposes the combination of several photomixing THz sources for overcoming the power limitations of this technology. Each element is placed in the gap of a balanced antenna. All the elements conform a 2D rectangular array. For avoiding issues related to having out-of-focus sources when using one electrically large silicon lens, two different strategies are considered: increasing the...
In this paper, a proof-of-concept sub-THz detector for its use in radio telescopes is presented. The detector is intended to work at room-temperature and to be suitable for cosmic microwave background B-mode polarization measurements, so a high sensitivity photon-countig receiver is required. The proposed detector is a practical arrangement of several receivers, each one working on the principle of...
In this paper, a general scheme for a sub-THz photon counting receiver working at room temperature is presented. Its working principle is based on nonlinear up-conversion of the sub-THz signal into the optical domain. For that, a lithium niobate (LiNbO3) WGM resonator is used in a double-resonant configuration. This system has theoretically shown capabilities towards photon counting. The concept is...
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