Input Connectors Research Articles

Разработка компактной широкополосной антенны со стабильной формой диаграммы направленности для применения в составе малоразмерных БпЛА

This paper presents a method to obtain a stable toroidal radiation pattern in a wide frequency range for a small-sized antenna based on a printed asymmetrical dipole. The method lies in the application of a broadband rectangular exciter (first arm) and matching it with a 50-Ohm input connector using a quarter-wave transformer based on microstrip transmission lines and a special form of a second arm. According to the proposed method, a printed antenna has been designed with two wide matching bands with reflection coefficient levels (module S11) of no more than minus 10 dB: 1677-2786 MHz (50%) and 3230-3801 MHz (16.2%). It forms a toroidal field in the frequency range of 1500-4000 MHz with a gain of at least 2 dBi in the direction of maximum radiation. The shape of the radiation pattern is quite stable over the entire frequency range; the maxima are polarized perpendicular to the antenna axis. The designed antenna was manufactured, and its characteristics were measured. This antenna is primarily applied to wireless communication systems for unmanned aerial systems and is intended to be installed on unmanned aerial vehicles to provide radio coverage in all azimuth directions. The manufactured antenna is compact (the antenna printed circuit board, without connector, is 63×22.5×1 mm3 or 0.35λmax×0.125λmax×0.006λmax); it is light (no more than 10 g including the connector), and its unique shape allows the antenna to be used without a dome, not reducing the aerodynamic properties of the vehicle.

A clinical investigation of force plate drift error on predicted joint kinetics during gait

Inverse dynamic analysis is a technique used during gait analysis to estimate intersegmental forces and net joint moments. Inverse dynamic calculations are susceptible to various forms of error. One such error is force plate drift, often produced by humidity condensing within the input connectors and electronics, causing an undesired change in output over time. This can be particularly concerning for movement laboratories where inverse dynamics are considered in clinical decision-making processes. Manufacturers will provide tolerance levels for drift. However, levels of acceptable drift are rarely considered from a clinical perspective. Therefore, this study aims to establish clinically acceptable limits of force plate drift error, induced by applying systematic errors to force plate channels, on predicted lower limb joint moments during gait. Gait data of 10 children with typical development were analysed and induced errors of 0.5 N, 1 N, 1.5 N, 3 N, 6 N and 12 N were incrementally applied to the horizontal and vertical force channels. Data were recalculated for each increment and mean profiles compared to an error free mean (±1SD) band. Error was deemed clinically significant when moments fell outside the mean (±1SD) band. Induced error at 6 N and above was sufficient to cause a clinically significant change. Sagittal and coronal plane moments at the hip were most affected, followed by the knee and then the ankle. While manufacturer guidelines for acceptable drift are usually well below 6 N, care is needed when using force plates over several minutes or more as drift may eventually exceed clinically acceptable limits.

Zero Voltage Switching Modified Boost Converter

Changing the position of the capacitor from the output to the position between the positive output and input connectors, leads to an interesting modification of the traditional Boost converter. The inrush current, when the converter is applied to a stable voltage source e.g. batteries in cars or a battery-buffered DC micro-grid, is suppressed, and the voltage stress across the capacitor is reduced. To reduce the switching losses and to reduce the disturbances caused by fast voltage rise- and fall-times, a zero voltage switching (ZVS) concept is applied and explained step by step and some interesting aspects of the converter are shown. All explanations are supported by calculations and simulations done with LTSpice.

The ultrafast pixel array camera system and its applications in high energy density physics.

Diagnostics in high energy density physics, shock physics, and related fields are primarily driven by a need to record rapidly time-evolving signals in single-shot events. These measurements are often limited by channel count and signal degradation issues on cable links between the detector and digitizer. We present the Ultrafast Pixel Array Camera (UPAC), a compact and flexible detector readout system with 32 waveform-recording channels at up to 10 Gsample/s and 1.8GHz analog bandwidth. The compact footprint allows the UPAC to be directly embedded in the detector environment. A key enabling technology is the PSEC4A chip, an eight-channel switch-capacitor array sampling device with up to 1056 samples/channel. The UPAC system includes a high-density input connector that can plug directly into an application-specific detector board, programmable control, and serial readout, with less than 5W of power consumption in full operation. We present the UPAC design and characterization, including a measured timing resolution of ∼20ps or better on acquisitions of sub-nanosecond pulses with minimal system calibrations. Example applications of the UPAC are also shown to demonstrate operation of a solid-state streak camera, an ultrafast imaging array, and a neutron time-of-flight spectrometer.

Battery Powered Inductive Welding System for Electrofusion Joints in Optical Fiber Microducts

Optical fiber microducts are joined together by mechanical joints. These mechanical joints are bulky, require more space per joint, and are prone to air pressure leakage and water seepage during service. A battery powered electrofusion welding system with a resistive-type joint has been recently developed to replace mechanical joints. These resistive-type electrofusion joints require physical connectors for power input. Due to a different installation environment, the power input connectors of resistive optical fiber microduct joints may corrode over time. This corrosion of connectors will eventually cause water seepage or air pressure leakage in the long run. Moreover, due to connector corrosion, resistive-type optical fiber microduct joints cannot be re-heated in future if the need arises. In this study, an inductively coupled electrofusion-type joint was proposed and investigated. This inductive-type electrofusion joint is not prone to long-term corrosion risk, due to the absence of power connectors. Inductive-type electrofusion joints can be re-heated again for resealing or removal in the long run, as no metal part is exposed to the environment. The battery powered inductive welding system can be easily powered with a 38 volts 160 watt-hour battery. The inductive-type electrofusion joint was welded within one second, and passed a 300-newton pull strength test and a 10-bar air pressure leakage test. It was demonstrated that the power input requirement for inductive electrofusion joints is 64% higher than that of resistive electrofusion joints. However, these inductive joints are relatively easy to manufacture, inexpensive, have no air leakage, and no water seepage risk in highly corrosive environments.

Дослідження параметрів дводіапазонних вібраторних антен НВЧ з коаксіальними і двопровідними шунтами

Subject and Purpose. Two types of new dual-frequency microwave antennas with coaxial and two-wire shunts are considered with a view to improve calculation methods of radio engineering and design parameters of the antennas of the kind. Methods and Methodology. The mathematical methods of equivalent long line and the method of integral equation and optimization of objective functions are used, involving set-point and current values of the voltage standing-wave ratios at the antenna input connectors in the two operating frequency bands. Results. The research and development results have been presented for two variants of dual-frequency (dual-band) vibrator antennas according to whether the shunts are placed inside metal radiating tubes or outside the central conductive rod of the antenna. The shunts are in coaxial and two-wire versions. As applied to the first antenna variant, the method of shunt length optimization upon a minimization of the objective functions yields desired values of antenna electrical parameters (voltage standing-wave ratio, radiation patterns, etc.). For the second antenna variant with both coaxial and two-wire external shunts and provided that the design and operation principle of these antennas are similar, conditions under which the double-frequency mode is possible have been determined for the first time. Conclusion. The proposed method of design and development of tubular dual-frequency vibrator antennas with coaxial shunts has been used to yield a two-frequency circular (elliptical) polarization turnstile antenna as part of sea buoys in the project "Ocean" of the National Space Agency of Ukraine and other spaceborne dual-frequency antennas. The new dual-frequency microstrip antenna discussed in this paper saves us significant drawbacks peculiar to the known dual-frequency antennas and can be used aboard spacecraft and other mobile objects due to its small size.

The comprehensive design of high efficiency monopole plasma antenna using surfaguide exciting method

In this study, designing procedure of a monopole plasma antenna excited by microwave surface waves was investigated. Improving the antenna efficiency, the surfaguide structure was used as a surface wave launcher at 2.45 GHz which could produce a plasma column and increase the plasma conductivity. Moreover, the antenna was fed directly via the input connector instead of the coupling sleeve in the conventional feeds using capacitive coupling method. Using these two techniques, the antenna performance was increased and it reduces the loss due to the coupling power from the source to the plasma column. Plasma column was modelled using Finite Element Method (FEM) with COMSOL MULTIPHYSICS software. The antenna parameters such as return loss, radiation pattern and gain were investigated using CST simulation. The designing procedure was performed for monopole antennas with lengths of l = 62 cm and l = 32 cm which resonate at 145 MHz and 200 MHz, respectively. The simulation results show acceptable adaptation in respect to the experimental measurement and increase significantly in the antenna gain compared with the previous ones.

Kinetic inductance traveling-wave amplifiers for multiplexed qubit readout

We describe a kinetic inductance traveling-wave (KIT) amplifier suitable for superconducting quantum information measurements and characterize its wideband scattering and noise properties. We use mechanical microwave switches to calibrate the four amplifier scattering parameters up to the device input and output connectors at the dilution refrigerator base temperature and a tunable temperature load to characterize the amplifier noise. Finally, we demonstrate the high fidelity simultaneous dispersive readout of two superconducting transmon qubits. The KIT amplifier provides low-noise amplification of both readout tones with readout fidelities of 83% and 89% and negligible effect on qubit lifetime and coherence.

Ultra-Broadband Modulator Packaging for Millimeter-Wave Applications

This paper reports the RF packaging design for electrooptic modulators operating in the millimeter-wave domain and discusses the RF and optical performances of the module. An LiNbO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> phase modulator has been integrated in a compact housing offering a 1.0-mm RF coaxial input connector. A coplanar waveguide on a low dielectric-loss alumina substrate has been designed to transition the RF field from the connector to the modulator. A RF insertion loss in the 1-2.5-dB range has been measured for the module over the 70-110-GHz bandwidth. A half-wave voltage comprised between 8.6 V at dc and 20 V at 110 GHz was calculated based on the observation of the optical modulation sidebands over the entire 110-GHz bandwidth. The optical insertion loss of the module was measured at 2.8 dB.

Evaluation of a Calorimetric Thermal Voltage Converter for RF–DC Difference up to 1 GHz

In this paper, we present a performance evaluation of the RF-DC transfer difference for a calorimetric thermal voltage converter (CTVC) designed by the National Research Council of Canada (NRC) at frequencies up to 1 GHz. In the first part of this paper, we describe a bilateral comparison of the RF-DC difference standards between the NRC and the National Metrology Centre of the Agency for Science, Technology and Research of Singapore, in the frequency band from 1 kHz to 100 MHz. A good agreement is observed between the two laboratories using the CTVC as a traveling standard. In the second part of this paper, we evaluate the performance of the CTVC at higher frequencies up to 1 GHz. In this part, RF-DC difference of the CTVC is mathematically modeled and experimentally evaluated in terms of the calibration factor of a thermistor mount and the reflection coefficients at its type-N input connector.

Improvement of the Voltage Dependence of High-Voltage AC–DC Transfer Differences at the NMIJ

A new AC-DC comparator system of 20-1000 V has been developed at the National Metrology Institute of Japan (NMIJ) for the calibration of ac-dc thermal voltage converters (TVCs), which are used as national ac-dc transfer standards. The ac-dc transfer differences of high-voltage transfer standards were evaluated by a traditional step-up procedure. The voltage dependence of the ac-dc transfer difference was observed in the earlier step-up procedures over 300 V, as reported by the latest international intercomparison. The experimental results for high-voltage TVCs with several different range resistors at the NMIJ suggest that the voltage dependence may primarily be caused by input connectors of range resistors and the change in the resistance value of the resistor and TVC modules due to heating from resistors. This paper describes the voltage dependence improvement of ac-dc transfer differences over 300 V at the NMIJ.

Focus on test and measurement

Focus on test and measurement

60‐GHz transceiver module with coplanar ribbon bonded planar millimeter wave bandpass filter

AbstractA small size 60‐GHz full duplex transceiver module is developed for high data rate millimeter wave wireless access link. To realize a compact and low cost transceiver module, a planar millimeter wave bandpass filter is integrated by using broadband coplanar ribbon‐bond interconnects in the module. The overall size of the module except input and output connectors is 50 mm × 75 mm × 23 mm. The measured RF output power is 16 dBm at 1‐dB compression, with conversion gain of 30.6 dB and the conversion gain of the receiver being 23.4 dB. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1212–1214, 2007; Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/mop.22399

Hybrid Ku-band low-noise amplifier for mobile DBS active phased-array antennas

In this article we present a two-stage Ku-band low-noise amplifier (LNA) using discrete pHEMT transistors on non-PTFE substrates for low-cost direct broadcast satellite (DBS) phased-array systems (patent pending). The vertical input configuration of the LNA lends itself to direct integration with input port of antenna modules of the phased array, which minimizes preamplification losses. DC decoupling between LNA stages is realized using interdigital microstrip capacitors such that the implementation reduces the number of discrete microwave components and thereby not only reduces the component and assembly costs but also decreases the standard deviation of such crucial parameters of phased-array systems as the end-to-end phase shift of the amplifier and the amplifier gain. Using the proposed printed decoupling capacitors, a cost reduction better than 30% of the original costs has been achieved. Additionally, we present a hybrid design procedure for the complete LNA, including its input and output connectors as well as packaging effects. This method is not based on parameter extraction, but encompasses electromagnetic (EM) field simulator results which are further combined using a high-level circuit simulator. According to the presented measurement results, the implemented Ku-band LNA has a noise figure better than 0.9 dB and a gain higher than 20 dB with a gain flatness of 0.3 dB over a 5% bandwidth. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.

A 60-GHz point-to-multipoint millimeter-wave fiber-radio communication system

A 60-GHz point-to-multipoint wireless access link with data rate of 156 Mb/s incorporating 60-GHz transceiver modules and full-duplex fiber-optic millimeter-wave transmission is developed for short-range applications such as indoor wireless local area networks and intelligent transport systems. For compact system configuration, a small-size millimeter-wave transceiver module with planar antennas is developed. The transceiver module is based on broadband planar integration and packaging of millimeter-wave circuits. The RF output power is +10 dBm and the measured 3-dB antenna beamwidth is 30/spl deg/. The total size of the developed 60-GHz transceiver module, except input and output connectors, is 50 mm /spl times/ 75 mm /spl times/ 35 mm. A point-to-point full duplex fiber-optic configuration is extended to the scheme with multiple access points (APs) by using a tree coupler and a dense wavelength division multiplexing multiplexer. The AP has a simple configuration without frequency conversion. The bit error rate and packet error rate performances of the 60-GHz fiber-radio access link are evaluated. Furthermore, the effect of the extension to the scheme with multiple APs is investigated.

Precision measurement method for cryogenic amplifier noise temperatures below 5 K

We report precision measurements of the effective input noise temperature of a cryogenic (liquid-helium temperature) monolithic-microwave integrated-circuit amplifier at the amplifier reference planes within the cryostat. A method is given for characterizing and removing the effect of the transmission lines between the amplifier reference planes and the input and output connectors of the cryostat. In conjunction with careful noise measurements, this method enables us to measure amplifier noise temperatures below 5 K with an uncertainty of 0.3 K. The particular amplifier that was measured exhibits a noise temperature below 5.5 K from 1 to 11 GHz, attaining a minimum value of 2.3 K/spl plusmn/0.3 K at 7 GHz. This corresponds to a noise figure of 0.034 dB/spl plusmn/0.004 dB. The measured amplifier gain is between 33.4 dB/spl plusmn/0.3 dB and 35.8 dB/spl plusmn/0.3 dB over the 1-12-GHz range.

APMP International Comparison of AC–DC Transfer Standards at the Lowest Attainable Level of Uncertainty

This paper presents preliminary results of the APMP.EM-K6a key comparison of AC-DC transfer conducted during 2000 to 2003. The AC-DC voltage transfer difference of the travelling standard was measured at 3 V and selected frequencies from 1 kHz to 1 MHz that included those of the CCEM-K6a key comparison. Also discussed are the methods used to compare thermal voltage converters with different input connectors, and to link the results to the parent Consultative Committee on Electricity and Magnetism (CCEM) comparison.

Calibration of HF thermal voltage converters using an asymmetrical tee

This paper discusses systematic errors in the AC-DC difference determination resulting from the comparison of thermal voltage converters with different input connectors. Tests of two asymmetrical tees, with GR-874 and type-N arms, as well as the internal tee of the NRC calorimetric thermal voltage converter, are presented.

3.5 mm coaxial power standard

A 3.5 mm twin line coaxial calorimeter is the first microwave power calorimeter in this line size to be constructed at the National Physical Laboratory. The instrument consists of two terminated coaxial lines with a length of high thermal resistance line between an APC-3.5 mm input connector and a tractorial load. The principle of operation is to measure RF power dissipated in one of the loads in terms of DC power dissipated in the other load. A temperature change due to the dissipation of power is detected by platinum resistance thermometers (PRTs) fixed on the coaxial line in the region of the load. Two PRT sensors connected in series on both sides of each coaxial line are incorporated in an AC bridge and detection circuit. Initially the output from the detection circuit is zero but once power is applied to the RF line the bridge goes out of balance. This signal is then used to control a feedback voltage to the DC line until the bridge output is returned to zero. The final DC feedback voltage that balances the bridge is then used to determine the RF power to the calorimeter. The instrument operates over the frequency range DC to 26.5 GHz at power levels 0.1–10 mW. The calculated effective efficiency for the calorimeter ranges from 102.4% at 0.1 GHz to 99.3% at 26.5 GHz. The VSWR of the RF line ranges from 1.006 at 1 GHz to 1.06 at 26.5 GHz with a maximum of 1.12 at 25.1 GHz.

Evaluation of low-frequency AC-DC difference of coaxially mounted thermal voltage converter

The paper describes results of measurements of AC-DC transfer difference of a coaxially mounted, thermal voltage converter. Results of experiments, conducted in the 1 kHz to 1 MHz frequency range, are compared with results of simulations, using a simplified model of the converter. AC-DC transfer difference contributions, originating in the input connector and elements of the coaxial enclosure, are presented.