Hawal Rashid

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We present the design and performance of a superconducting 90° hybrid covering a full octave bandwidth from 4 to 8 GHz. The hybrid is designed using the Lange coupler layout. The novel features of this quadrature hybrid include superconducting niobium (Nb) transmission lines, air bridges to connect the fingers of the coupler and a bias-T integrated(More)
We present here the design and characterization of an intermediate frequency (IF) assembly comprising a compact 90° hybrid chip (coupled line coupler - Lange coupler- coupled line coupler), two bias-T circuits for biasing the superconductor-insulator-superconductor (SIS) mixers, and two transmission-line circuits. Specifically, the miniaturized(More)
We present a design and synthesis procedure for a new 90 <sup>&#x00B0;</sup> waveguide hybrid with ultra-low amplitude imbalance. This novel hybrid design is based on Reed's multiple branch waveguide hybrid. The primary feature of this quadrature hybrid design is the introduction of a controllable ripple in the operational band by, firstly changing the(More)
We present performance of the first ALMA Band 5 production cartridge, covering frequencies from 163 to 211 GHz. Atacama Large Millimeter/sub-millimeter Array (ALMA) Band 5 is a dual polarization, sideband separation (2SB) receiver based on all Niobium (Nb) superconductor-insulator-superconductor (SIS) tunnel junction mixers, providing 16 GHz of(More)
We present a new design concept for a 90&#x00B0; waveguide hybrid and its implementation. This novel hybrid design is based on a multiple branch waveguide hybrid. The primary feature of this quadrature waveguide hybrid is the introduction of a controllable ripple in the operational band for achieving a better overall amplitude imbalance. This design concept(More)
This paper presents a tentative modelling of Superconductor-Insulator-Superconductor (SIS) junction used as frequency multiplier. The model is tested against the experimental data presented earlier and demonstrates good agreement between the measured data and simulation. Such a model will improve understanding of the SIS junction used as frequency(More)
In this letter we present the characterization of the first frequency up-converter using distributed superconducting tunnel junctions. The power of the frequency up-converted signal was large enough to pump an SIS mixer. The efficiency of the distributed superconducting tunnel junction is 11-22 % for a fractional bandwidth of 7% with excellent spectral line(More)
A novel broadband THz microsensor for room temperature imaging applications is presented. The sensor's response time is optimized by tuning its structural design, using Monte-Carlo and transient FEM simulations. The optimized and robust sensor shows a 3.5 THz bandwidth (0.5&#x2013;4THz) and a response time of &#x007E;40ms, suitable for real time radio(More)
In this paper, we present the analysis, design, and characterization of the first frequency multiplier using distributed superconductor-insulator-superconductor (SIS) junctions. We derived analytical expressions describing the properties of the distributed SIS junction as a frequency multiplier. The modeling of the distributed SIS junctions shows that high(More)
We present a new design approach for the 90&#x00B0; directional coupler with very low amplitude imbalance. The primary feature of this quadrature coupler is the introduction of a controllable ripple in the operational band for achieving a better overall amplitude balance. This design concept is demonstrated through a 90&#x00B0; branch-line hybrid for the(More)