Multifrequency seashell antenna based on resonant cold-electron bolometers with kinetic Inductance Nanofilters for CMB measurements

Abstract

A novel type of the seashell slot antenna with internal filters by the capacitance of resonant cold-electron bolometers (RCEB) and kinetic inductance of the NbN superconducting nanostrip has been realized for multifrequency pixels. Seashell antenna gives the opportunity to connect opposite slots by coplanar waveguides (CPW) instead of microstrip lines (MSL). A conventional multifrequency pixel combines a wideband antenna and narrowband filters with long microstrip lines with unavoidable losses and overlaps. Another problem is the frequency dependent beam width due to a fixed pixel diameter for multiple frequencies. The main advantage of the seashell antenna with nano-filters is independent tuning of the separate pairs of slots for each frequency avoiding frequency dependence of the beam width. We used λ/2 slots for 75 and 105 GHz, feeding by CPW near the end of slots for RF matching. Each RCEB includes two SIN (Superconductor-Insulator-Normal) tunnel junctions with a nano-absorber and NbN kinetic inductance of 450 or 310 pH. SIN junctions had capacitances of 9.3 and 7.2 fF and absorber matched to a wave impedance of the antenna near 50 Ohm. Kinetic inductance value was estimated at the level of 35 pH/sq. RF testing was done at 300 mK irradiating this chip by sweep generator from 60 to 120 GHz. The response curves showed clear resonances at 75 and 105 GHz with a quality factor of 10 and 7. These experiments confirm that the seashell antenna with the internal RCEB filters can be used for frequency selection in compact multiband pixels.

Spectral Characteristics of the Double-Folded Slot Antennas with Cold-Electron Bolometers for the 220/240 GHz Channels of the LSPE Instrument

“…These antennas have been tested with various sensors, such as bismuth bolometers [13], quasioptical SIS mixers [14], and so on. The concept of double slot antenna has also been applied in the seashell antenna [11,12,15,16] which has been designed for use with CEBs and suggested for COrE project [17]. To make a single cell of the antenna matrices, we actually take one frequency channel of the seashell antenna.…”

“…We perform numerical simulations of a single antenna cell in the CST Microwave Studio software package. The method of calculation of frequency characteristics of the antenna cell is described in [15,16]. First, we calculate the S-parameter of the system, and then Z-parameter in 3D electromagnetic simulations using the frequency domain solver.…”

Response of a Cold-Electron Bolometer on THz Radiation from a Long YBa2Cu3O7−δ Bicrystal Josephson Junction

“…The cold-electron bolometer (CEB) is an attractive candidate for these measurements because the decoupling of the phonon and electron subsystems in the tiny absorber gives it such advantages as high sensitivity and high saturation power [3,4] as well as the immunity to cosmic rays [5]. CEBs can be used for on-chip LC-filtering due to a series resonance of the SIN junction capacitance and the kinetic inductance of the NbN strip [6][7][8] or the reactance of slot antennas connected by coplanar lines [9,10]. This property is used for the creation of multichroic pixels with CEBs.…”

THz Properties of Long YBaCuO Bicrystal Josephson Junction Studied with a Cold-Electron Bolometer

“…The cold-electron bolometer (CEB) is an attractive candidate for these measurements because the decoupling of the phonon and electron subsystems in the tiny absorber gives it such advantages as high sensitivity and high saturation power [3,4] as well as the immunity to cosmic rays [5]. CEBs can be used for on-chip LC-filtering due to a series resonance of the capacitance of SIN junctions and the kinetic inductance of the NbN strip [6][7][8] or the reactance of slot antennas connected by coplanar lines [9,10]. This property is used for the creation of multichroic pixels with CEBs.…”