Superconducting filter for radio astronomy using interdigitated, capacitively loaded spirals

Bolli, Pietro; Huang, F.

doi:10.1007/s10686-012-9289-y

Cited by 12 publications

(7 citation statements)

References 14 publications

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“…The insertion loss of this component is estimated at 0.01 dB at 20 K and the equivalent noise temperature is negligible.  A cryogenic bandpass filter, which is proposed in [16].…”

Section: B P-band Receiver Cryogenic Rf Pathmentioning

confidence: 99%

The Coaxial L-P Cryogenic Receiver of the Sardinia Radio Telescope

et al. 2022

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The design and characterization of the coaxial dual-band L-P radio astronomical receiver for the prime focus of the Sardinia radio telescope are presented. The main feature of this receiver is to allow simultaneous radio astronomical observations in the P (305 -410 MHz) and L (1.3 -1.8 GHz) frequency bands. This functionality, which has been requested by the Pulsar research group at the National Institute for Astrophysics to estimate, among the others, the ionospheric dispersion in Pulsar observation, is currently missing in any other radio astronomical facility throughout the world. Also, single band operation is ensured by the proposed design both in linear and circular polarization, making this L-P receiver an ideal instrument for a wide range of radio astronomical and space applications. Some components of the receiver chain have been housed inside a cryostat and refrigerated at 20 K to reduce the noise temperature, resulting in a good performance compared to the receivers of other large radio telescopes. Several challenging issues have been faced in the design, mainly due to the large dimension and weight of the overall structure to be mounted in the prime focus position. Moreover, the design of the cryostat was constrained by the limited space available in the direction of the optical axis inside the focal cabin of the radio telescope, requiring a compact and light realization of the components of the receiver chain. This called for a home-made design of several devices, requiring a strong collaborative effort by researchers, engineers, and astronomers.

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“…The insertion loss of this component is estimated at 0.01 dB at 20 K and the equivalent noise temperature is negligible.  A cryogenic bandpass filter, which is proposed in [16].…”

Section: B P-band Receiver Cryogenic Rf Pathmentioning

confidence: 99%

The Coaxial L-P Cryogenic Receiver of the Sardinia Radio Telescope

et al. 2022

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“…Analyzing the plot of Figure 11a, it is visible that the GAIA board generates narrowband signals at 4,12,32,36,192, and 875 MHz with regard to the P-band [53]. This last RFI represents the highest of signals gave off by GAIA in P-band, but it does not represent an issue for the receiver, since it is far from the P-band receiver bandwidth (i.e., the bandwidth of the P-band feed is 305-410 MHz).…”

Section: Mitigation Of the Rfis Generated By The Electronic Control S...mentioning

confidence: 99%

“…With the aim of maximizing the scientific research results and extending them to new high frequencies (up to 116 GHz) not yet covered by SRT, INAF has recently expressed an interest to upgrade the telescope. For these reasons, a National Operational Program (PON) funding [25] has been allocated to INAF by the Italian Ministry of University and Research, with the aim to install on the telescope four new receivers that operate in Q-band (33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50) and W-band (70-116 GHz) [25][26][27]. The works relating to the PON project have imposed a stop on the SRT operations and, consequently, the temporary dismantling of the old receivers (P-band, L-band, C-band and K-band [9], respectively).…”

Section: Introductionmentioning

confidence: 99%

“…Downstream from this component (see Figure 3), there is a commercial coaxial mechanical switch (model Agilent 8761B [35]), provided for the Pband low noise amplifier (LNA) isolation in case of high self-produced RFIs [29]. The next component of the Dewar signal acquisition chain is a cryogenic high-temperature superconducting (HTS) band pass filter (BPF) [36]. This filter is used before the LNA with the aim to reject high RFIs slightly outside the receiver bandwidth, which would be amplified in an undesirable mode by the LNA.…”

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confidence: 99%

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Upgrading of the L-P Band Cryogenic Receiver of the Sardinia Radio Telescope: A Feasibility Study

Ladu

Schirru

Gaudiomonte

et al. 2022

Sensors

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The Sardinia Radio Telescope is a quasi-Gregorian system with a shaped 64 m diameter primary reflector and a 7.9 m diameter secondary reflector. It was designed to operate with high efficiency across the 0.3–116 GHz frequency range. The telescope is equipped with a cryogenic coaxial dual-frequency L-P band receiver, which covers a portion of the P-band (305–410 MHz) and the L-band (1300–1800 MHz). Although this receiver has been used for years in its original design, with satisfactory results, it presents some parts that could be upgraded in order to improve the performances of the system. With the passing of time and with technology advances, the presence of unwanted human-made signals in the area around the telescope, known as radio frequency interferences, has grown exponentially. In addition, the technology of the receiver electronic control system became obsolete and it could be replaced with next-generation electronic boards, which offer better performances both service reliability and low generation of unwanted radio frequency signals. In this paper, a feasibility study for improving the L-P band receiver is discussed, taking into account the mitigation of the main radio frequency interferences. With this study, it is possible to have a sensitive instrument that can be used for scientific research at low frequencies (P- and L-bands), which are usually populated by signals from civil and military mobile communications, TV broadcasting and remote sensing applications.

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“…RFI mitigation in radio astronomy: Active RFI mitigation has become a necessary practice in the radio astronomy community. Known persistent and fixed sources of RFI are highly attenuated at the front-end of the receiver using series of analog superconductive filters [37], [38], but frequencies with high RFI density (e.g. FM or Digital Video Broadcast band) are usually simply avoided by design.…”

Section: Related Workmentioning

confidence: 99%

Collaboration with Cellular Networks for RFI Cancellation at Radio Telescope

Chakraborty¹,

Hellbourg²,

Careem³

et al. 2022

Preprint

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The growing need for electromagnetic spectrum to support the next generation (xG) communication networks increasingly generate unwanted radio frequency interference (RFI) in protected bands for radio astronomy. RFI is commonly mitigated at the Radio Telescope without any active collaboration with the interfering sources. In this work, we provide a method of signal characterization and its use in subsequent cancellation, that uses Eigenspaces derived from the telescope and the transmitter signals. This is different from conventional time-frequency domain analysis, which is limited to fixed characterizations (e.g., complex exponential in Fourier methods) that cannot adapt to the changing statistics (e.g., autocorrelation) of the RFI, typically observed in communication systems. We have presented effectiveness of this collaborative method using realworld astronomical signals and practical simulated LTE signals (downlink and uplink) as source of RFI along with propagation conditions based on preset benchmarks and standards. Through our analysis and simulation using these signals, we are able to remove 89.04% of the RFI from cellular networks, which reduces excision at the Telescope and capable of significantly improving throughput as corrupted time frequency bins data becomes usable.

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Superconducting filter for radio astronomy using interdigitated, capacitively loaded spirals

Cited by 12 publications

References 14 publications

The Coaxial L-P Cryogenic Receiver of the Sardinia Radio Telescope

The Coaxial L-P Cryogenic Receiver of the Sardinia Radio Telescope

Upgrading of the L-P Band Cryogenic Receiver of the Sardinia Radio Telescope: A Feasibility Study

Collaboration with Cellular Networks for RFI Cancellation at Radio Telescope

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