Bandwidth and SNR of Small Receiving Antennas: To Match or Not to Match

Sarabandi, Kamal; Rao, Menglou

doi:10.1109/tap.2022.3215229

Cited by 6 publications

(5 citation statements)

References 12 publications

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“…In this case, the parameter α represents an increase in overall system gain while leaving directivity unchanged, i.e., amplification without changing the antenna's radiation pattern. Like in the previous example, this situation leads inevitably to increased effective noise temperature (33) for any nonzero value of out-of-band coupling β, but also carries the additional consequence that, by (29), the received SNR must also lower as well. This is a restatement of the fact that antenna gain does little to improve system performance in externally noise-limited systems.…”

Section: Discussionmentioning

confidence: 80%

“…appearing in ( 27)- (29). The above expression constitutes the core theoretical development of the paper.…”

Section: Summary Of Effective Noise Temperaturesmentioning

confidence: 97%

“…1, where all signals incident upon a receiver propagate as plane waves. The noise intensity ñ is incident upon a receiver from all directions k. In general, the noise intensity may be angularly dependent [27], but here we follow a standard first-order simplification [28, §2.18] and assume an isotropic thermal noise corresponding to the frequency-dependent background temperature T b (ω) [29],…”

Section: Signal and Noise Modelsmentioning

confidence: 99%

“…The scaling factor α represents an increase in the signal frequency effective aperture (analogous to increased directivity) while the factor β controls the relative magnitude of the first-harmonic cross-frequency effective aperture terms. As in the LTI case, the SNR for the time-varying receiver can be calculated using (29) and normalized by S 0 /(k B B).…”

Section: Demonstrative Analysismentioning

confidence: 99%

See 3 more Smart Citations

Scattering Properties of Spherical Time-Varying Conductive Shells

Schab

Shirley

Kerby-Patel

2022

IEEE Trans. Antennas Propagat.

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The equivalent external noise temperature of timevarying antennas is studied using the concept of cross-frequency effective aperture, which quantifies the intermodulation conversion of external noise across the frequency spectrum into a receiver's operational bandwidth. The theoretical tools for this approach are laid out following the classical method for describing external noise temperature of linear time-invariant antennas, with generalizations made along the way to capture the effects of time-varying components or materials. The results demonstrate the specific ways that a time-varying system's noise characteristics are dependent on its cross-frequency effective aperture and the broadband noise environment. The general theory is applied to several examples, including abstract models of hypothetical systems, antennas integrated with parametric amplification, and time-modulated arrays.

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Section: Discussionmentioning

confidence: 80%

“…appearing in ( 27)- (29). The above expression constitutes the core theoretical development of the paper.…”

Section: Summary Of Effective Noise Temperaturesmentioning

confidence: 97%

Section: Signal and Noise Modelsmentioning

confidence: 99%

Section: Demonstrative Analysismentioning

confidence: 99%

See 2 more Smart Citations

Scattering Properties of Spherical Time-Varying Conductive Shells

Schab

Shirley

Kerby-Patel

2022

IEEE Trans. Antennas Propagat.

View full text Add to dashboard Cite

show abstract

“…Non-foster matching techniques based on negative impedance converters (NIC) have also been proposed and studied [22], [23], [24], yet it has been concluded in [24] that this technique does not offer system advantages in terms of noise figure, largely due to the added noise of the NIC circuit. Recently, several experimental works [25], [26], [27], [28] demonstrated that traditional matching strategies of ESAs did not result better signal to noise performance or better noise bandwidth in experiments comparing with direct connection of ESAs to a buffer amplifier [25], an op-amp [26] or parametric amplifiers [27], [28]. These findings call for a re-evaluation of the noise matching strategy for receivers with electrically small antennas, particularly given the fact that active electronics has undoubtfully improved significantly over the past half a century.…”

Section: Introductionmentioning

confidence: 99%

Theory of Broadband Noise Matching for HF/VHF Receivers With Electrically Small Antennas

Wang

2023

IEEE Access

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A general theory on noise matching performance of receivers with electrically small antennas (ESAs) emphasizing HF (3MHz to 30MHz) and VHF (30MHz to 300MHz) applications is presented through theoretical analyses, discussions, and circuit simulations with practical device models from a state-of-the art semiconductor technology. The theory considers all the noise sources and their interplay. The impact on the noise performance from both the physical constraint of the ESA in terms of its radiation quality factor and the scaling of transistor technology and periphery such as gate resistance, gate cutoff frequency and transition frequency has been discussed. Two receiver examples, one with electrically small dipole and the other with electrically small loop are studied with full-wave simulations. The antenna equivalent models are then connected to low noise amplifiers designed with the state-of-the-art Gallium Nitride (GaN) transistor models to evaluate the noise performance of the systems and compared against the theory. It is demonstrated that both the noise figure and its bandwidth can be significantly improved over traditional matching strategy when optimized active direct matching is applied at the price of increased device periphery and power consumption. In particular, the bandwidth of such low noise matching can be orders of magnitude wider than the antenna's conjugate impedance matching bandwidth that is defined by Harrington-Chu's limit.INDEX TERMS Broadband matching, electrically small antennas, GaN transistors, HF antennas, low noise matching, receivers, VHF antennas.

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Performance of antenna-based and Rydberg quantum RF sensors in the electrically small regime

Backes,

Elgee,

LeBlanc

et al. 2024

Applied Physics Letters

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Rydberg atom electric field sensors are tunable quantum sensors that can perform sensitive radio frequency measurements. Their qualities have piqued interest at longer wavelengths where their small size compares favorably to impedance-matched antennas. Here, we compare the signal detection sensitivity of cm-scale Rydberg sensors to similarly sized room-temperature electrically small antennas with active and passive receiver backends. We present and analyze effective circuit models for each sensor type, facilitating a fair sensitivity comparison for cm-scale sensors. We calculate that contemporary Rydberg sensor implementations are less sensitive than unmatched antennas with active amplification. However, we find that idealized Rydberg sensors operating with a maximized atom number and at the standard quantum limit may perform well beyond the capabilities of antenna-based sensors at room temperature, the sensitivities of both lying below typical atmospheric background noise.

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Bandwidth and SNR of Small Receiving Antennas: To Match or Not to Match

Cited by 6 publications

References 12 publications

Scattering Properties of Spherical Time-Varying Conductive Shells

Scattering Properties of Spherical Time-Varying Conductive Shells

Theory of Broadband Noise Matching for HF/VHF Receivers With Electrically Small Antennas

Performance of antenna-based and Rydberg quantum RF sensors in the electrically small regime

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