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This communication proposes a broadband and efficient integrated focal plane array solution based on a near-field focused connected array of slots. The focused aperture provides: 1) broadband and highly efficient illumination of the quasi-optical system and 2) scanning capabilities within a focusing system. The connected array antenna in turn allows for a fully integrated solution that can synthesize a focused aperture while providing broadband impedance matching. Focused connected array antennas enable the coupling to a reflector system over bandwidths in excess of one octave and with aperture efficiencies in excess of 60%. To demonstrate the concept, we present two printed circuit board (PCB) prototypes operating in the band 3–6 GHz and yielding more than 60% reflector aperture efficiency under broadside illumination and allowing to scan one beamwidth at the lowest frequency with a frequency-averaged scan loss of 0.2 dB. The feasibility of scaling this concept to THz frequencies and with dynamic beam-steering capabilities is discussed in the context of a superconducting device. [ABSTRACT FROM AUTHOR]

We present the design, fabrication, and characterization of a broadband leaky lens antenna for broadband, spectroscopic imaging applications. The antenna is designed for operation in the 300–900 GHz band. We integrate the antenna directly into an Al-NbTiN hybrid microwave kinetic inductance detector (MKID) to measure the beam pattern and absolute coupling efficiency at three frequency bands centered around 350, 650, and 850 GHz, covering the full antenna band. We find an aperture efficiency $\eta _{ap} \approx 0.4$ over the whole frequency band, limited by lens reflections. We find a good match with simulations for both the patterns and efficiency, demonstrating a 1:3 bandwidth in the submillimeter wavelength range for future on-chip spectrometers. [ABSTRACT FROM AUTHOR]

Microwave kinetic inductance detectors (MKIDs) are the most attractive radiation detectors for far-infrared and sub-mm astronomy. They combine ultimate sensitivity with the possibility to create very large detector arrays, in excess of 10000 pixels. This is possible by reading-out the arrays using RF frequency division multiplexing, which allows multiplexing ratios in excess of 1000 pixels per readout line. We describe a novel readout system for large arrays of MKIDs, operating in a 2-GHz band in the 4–8-GHz range. The readout, which is a combination of a digital front- and back-end and an analog upconverter and downconverter system, can read out up to 4000 detectors simultaneously with 1-kHz data rate. The system achieves a readout noise power spectral density of -\text 98 dBc/Hz while reading 1000 carriers simultaneously, which scales linear with the number of carriers. We demonstrate that 4000 state-of-the-art aluminium-NbTiN MKIDs can be read out without deteriorating their intrinsic performance. [ABSTRACT FROM AUTHOR]