Experimental investigation of a twin-bridges superconducting switch
27th International Symposium on Space Terahertz Technology (ISSTT 2016) National Radio Astronomy Observatory (2017)
Abstract:
We present the design and some preliminary measured results of a planar superconducting on/off switch comprising two niobium nitride (NbN) bridges deposited across the slotline section of a unilateral finline. The two bridges are separated by a distance of λ/4, such that the superconducting impedance of the bridges could be cancelled out at the resonance frequency. Both the NbN bridges were switched from the superconducting state to the normal state via a bias current exceeding the critical current of the NbN film. A millimetre wave source calibrated with a terahertz power meter is used to illuminate the switch, and the response of the switch in each state was measured using a superconductor-insulator-superconductor (SIS) chip as a direct detector. Preliminary measured results agreed generally well with our simulations, especially when the multiple wave reflection effect is included in our model.A planar microstrip coupler with enhanced power coupling
Electronics Letters Institution of Engineering and Technology 53:1 (2016) 34-36
Abstract:
In this Letter, we present the design of a planar microstrip coupler where power coupling between two parallel microstrip lines can easily be controlled. Enhancement of power coupling is done via two small slots in the ground plane underneath the microstrip pair. The ground plane slots force the field lines near the edge of each microstrip to cross to the adjacent microstrip. The magnitude of the power coupling can easily be controlled by adjusting the length of the slots. Here, we describe the operation of a microstrip coupler, and present the design of a1 X 4 power distributor array that can be used to distribute the input microwave power uniformly to four branch lines arranged in a row. We also present the measured responses of the array, and show that the performance agree very well with simulated results.The Far Infrared Spectroscopic Explorer (FIRSPEX): probing the lifecycle of the ISM in the universe
Proceedings of SPIE SPIE, the international society for optics and photonics 9904 (2016) 99042k-99042k-7
The Far InfraRed Spectroscopic EXplorer (FIRSPEX)
27th International Symposium on Space Terahertz Technology, ISSTT 2016 Society of Photo-Optical Instrumentation Engineers (2016)
Abstract:
The Far InfraRed Spectroscopic EXplorer (FIRSPEX) is a novel concept for an astronomy satellite mission that will revolutionise our understanding of the properties of the Interstellar Medium (ISM) and star formation through velocity resolved spectroscopic observations at multi-terahertz frequencies. FIRSPEX comprises a fully cryogenic (~4K) heterodyne payload and a ~1.2 m primary antenna to scan the sky in a number of discreet spectroscopic channels delivering 3- dimensional spectral information. The spectral range selected contains important molecular, atomic and ionic species; the majority of which cannot be observed from the ground. FIRSPEX is UK led with additional contributions from partners throughout Europe. FIRSPEX opens up a relatively unexplored parameter space that will produce an enormously significant scientific legacy by focusing on the properties of the multi-phase ISM, the assembly of molecular clouds in our Galaxy and the onset of star formation topics which are fundamental to our understanding of galaxy evolution.Experimental Investigation of a Superconducting Switch at Millimetre Wavelength
IEEE Transactions on Terahertz Science & Technology Institute of Electrical and Electronics Engineers (IEEE) (2015)