In general, Micropower Impulse Radar (MIR) depends on Ultra-Wideband (UWB) transmission systems. UWB technology can supply innovative new systems and products that have an obvious value for radar and communications uses. Important applications include bridge-deck inspection systems, ground penetrating radar, mine detection, and precise distance resolution for such things as liquid level measurement. Most of these UWB inspection and measurement methods have some unique qualities, which need to be pursued. Therefore, in considering changes to Part 15 the FCC needs to take into account the unique features of UWB technology. MIR is applicable to two general types of UWB systems: radar systems and communications systems. Currently LLNL and its licensees are focusing on radar or radar type systems. LLNL is evaluating MIR for specialized communication systems. MIR is a relatively low power technology. Therefore, MIR systems seem to have a low potential for causing harmful interference to other users of the spectrum since the transmitted signal is spread over a wide bandwidth, which results in a relatively low spectral power density.

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Response to FCC 98-208 notice of inquiry in the matter of revision of part 15 of the commission's rules regarding ultra-wideband transmission systems

IEEE International Solid-State Circuits Conference

High quality on-chip microwave resonators have recently found prominent new applications in quantum optics and quantum information processing experiments with superconducting electronic circuits, a field now known as circuit quantum electrodynamics (QED). They are also used as single photon detectors and parametric amplifiers. Here we analyze the physical properties of coplanar waveguide resonators and their relation to the materials properties for use in circuit QED. We have designed and fabricated resonators with fundamental frequencies from 2 to 9 GHz and quality factors ranging from a few hundreds to a several hundred thousands controlled by appropriately designed input and output coupling capacitors. The microwave transmission spectra measured at temperatures of 20 mK are shown to be in good agreement with theoretical lumped element and distributed element transmission matrix models. In particular, the experimentally determined resonance frequencies, quality factors, and insertion losses are fully and consistently explained by the two models for all measured devices. The high level of control and flexibility in design renders these resonators ideal for storing and manipulating quantum electromagnetic fields in integrated superconducting electronic circuits.

Coplanar waveguide resonators for circuit quantum electrodynamics

Reactive matching is extended to wide bandwidths using the impedance property of LC-ladder filters. In this paper, we present a systematic method to design wideband low-noise amplifiers. An SiGe amplifier with on-chip matching network spanning 3-10 GHz delivers 21-dB peak gain, 2.5-dB noise figure, and -1-dBm input IP3 at 5 GHz, with a 10-mA bias current.

A 3-10-Ghz low-noise amplifier with wideband LC-ladder matching network

The aim of this paper is to show the possibility to harvest RF energy to supply wireless sensor networks in an outdoor environment. In those conditions, the number of existing RF bands is unpredictable. The RF circuit has to harvest all the potential RF energy present and cannot be designed for a single RF tone. In this paper, the designed RF harvester adds powers coming from an unlimited number of sub-frequency bands. The harvester’s output voltage ratios increase with the number of RF bands. As an application example, a 4-RF band rectenna is designed. The system harvests energy from GSM900 (Global System for Mobile Communications), GSM1800, UMTS (Universal Mobile Telecommunications System) and WiFi bands simultaneously. RF-to-dc conversion efficiency is measured at 62% for a cumulative ${-}{\hbox{10}}$ -dBm input power homogeneously widespread over the four RF bands and reaches 84% at 5.8 dBm. The relative error between the measured dc output power with all four RF bands on and the ideal sum of each of the four RF bands power contribution is less than 3%. It is shown that the RF-to-dc conversion efficiency is more than doubled compared to that measured with a single RF source, thanks to the proposed rectifier architecture.

A Multi-Band Stacked RF Energy Harvester With RF-to-DC Efficiency Up to 84%

The present letter describes the design of an energy harvesting circuit on a one-sided directional flexible planar antenna. The circuit is composed of a flexible antenna with an impedance matching circuit, a resonant circuit, and a booster circuit for converting and boosting radio frequency power into a dc voltage. The proposed one-sided directional flexible antenna has a bottom floating metal layer that enables one-sided radiation and easy connection of the booster circuit to the metal layer. The simulated output dc voltage is 2.89 V for an input of 100 mV and a 50 Ω power source at 900 MHz, and power efficiency is 58.7% for 1.0 × 107 Ω load resistance.

Energy Harvesting Circuit on a One-Sided Directional Flexible Antenna

Effects of a damping resistance on noise characteristics of a dc SQUID are studied theoretically, where the damping resistance is in shunt with a loop inductance of the SQUID. An analytical expression for the energy resolution of the SQUID is obtained, with which the relation between the damping resistance and the energy resolution is studied in detail. It is shown that an optimum value of the damping resistance exists, which is determined by the tradeoff between the improvement of the transfer function and the additional noise due to the damping resistance. Optimum values of the damping resistance are about twice the shunt resistance of the SQUID and vary slightly with SQUID modulation parameter β. For optimum damping, the energy resolution is improved, compared with the case without the damping resistance. This means that the SQUID with large β can be used without significant degradation of the performance, i.e., the previous restriction of β=1 can be loosened. The analytical results agree quantitatively with numerical ones.

Noise characteristics of a dc SQUID with a resistively shunted inductance. II. Optimum damping

An analytical expression for the kinetic inductance of the superconducting coplanar waveguide is given using the conformal mapping technique. This expression is shown to be in good agreement with experimental results obtained from the temperature dependence of the resonant frequency of the NbN coplanar waveguide resonators, especially in the case of a film thickness smaller than the magnetic penetration depth. It is also shown that the magnetic penetration depth of the superconducting thin films can be evaluated by this method.

https://iopscience.iop.org/article/10.1143/JJAP.33.5708/pdf

Kinetic Inductance of Superconducting Coplanar Waveguides

The effect of a damping resistance on the relation between a voltage V and a magnetic flux Φ of a dc SQUID is studied theoretically for the case with a large SQUID parameter βL=2LI0/Φ0 , where L is a loop inductance, I0 is a critical current, and Φ0 is the flux quantum. An approximate analytical expression for the V‐Φ relation is obtained by replacing the Josephson junctions with ac current generators. It is shown that the V‐Φ relation becomes almost independent of the value of βL in the case of large damping. As a result, the conversion efficiency dV/dΦ is not degraded even for large βL , as is not the case with a conventional SQUID without the damping resistance. This result indicates the possibility to use the SQUID with large βL for the improvement of the coupling between the SQUID and the input coil without the degradation of the conversion efficiency. Effect of the capacitance is also studied. It is shown that the effect of the capacitance becomes remarkable for the case of βc≳0.4 , where βc is the ...

Effect of damping resistance on voltage versus flux relation of a dc SQUID with large inductance and critical current

In order to determine transmission line parameters of superconducting coplanar striplines with thickness smaller than the magnetic penetration depth of the striplines, in which the influences of enlarged kinetic inductance and strongly nonuniform current distribution make it useless to apply the conventional design formula developed for normal conductors, we have conducted theoretical and experimental studies on the geometrical effects of the kinetic inductance and the microwave loss of the thin coplanar striplines. The analytical expression for the kinetic inductance of the coplanar stripline is given using the conformal mapping technique, and it is shown with the London equation and the two fluid-model that the microwave loss is directly proportional to the kinetic inductance. The comparison has been made between theory and experiment concerning the kinetic inductance and the microwave quality factor of NbN coplanar striplines with various thicknesses and widths. It is shown that the observed characteristics are well modeled by the analytical expression.

https://iopscience.iop.org/article/10.1143/JJAP.31.3844/pdf

Keiji Yoshida

Papers

Energy Harvesting Circuit on a One-Sided Directional Flexible Antenna

Noise characteristics of a dc SQUID with a resistively shunted inductance. II. Optimum damping

Kinetic Inductance of Superconducting Coplanar Waveguides

Effect of damping resistance on voltage versus flux relation of a dc SQUID with large inductance and critical current

Modeling of Kinetic-Inductance Coplanar Striplin with NbN Thin Films