TY - GEN
T1 - A 700 GHz unilateral finline SIS mixer fed by a multi-flare angle smooth-walled horn
AU - Tan, Boon Kok
AU - Yassin, Ghassan
AU - Grimes, Paul
AU - Leech, Jamie
AU - Jacobs, Karl
AU - Withington, Stafford
AU - Tacon, Mike
AU - Groppi, Christopher
PY - 2010
Y1 - 2010
N2 - 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.
AB - 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.
KW - Silicon-On-Insulator technology
KW - Superconductor-Insulator-Superconductor mixer
KW - direct-drilling technique
KW - smooth-walled horn
KW - unilateral finline taper
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U2 - 10.1117/12.856711
DO - 10.1117/12.856711
M3 - Conference contribution
AN - SCOPUS:77956213903
SN - 9780819482310
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V
T2 - Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V
Y2 - 29 June 2010 through 2 July 2010
ER -