Two-port Device Research Articles

TE013 Mode High Temperature Superconductor Millimeter Resonator

This paper describes a TE013 mode dielectric resonator at 36.098 GHz. The dielectric resonator was formed by sandwiching a cylindrical piece of polished dielectric (sapphire) rod between two GdBa2Cu3O7−x (GBCO) High Temperature Superconductor (HTS) thin films. The resonator was tested as a two-port device at a temperature of 77 K. A 62700 unload quality factor Q0 was obtained. The surface resistance (Rs) of the HTS film had been determined as 9.4 mΩ at 77 K and 36 GHz.

Surface Acoustic Waves And Guided Optical Waves In AlGaN Films

AbstractAlxGa1-xN layers grown by MOCVD on sapphire substrates have been tested using the surface acoustic wave and guided optical wave techniques. Samples with molar fraction of Al up to 0.36 have been investigated. The parameters S11 of single surface acoustic wave transducers and S12 of two-port devices have been measured with the network analyzer. The values of the surface acoustic wave velocity and electromechanical coupling coefficient for the layer-substrate structure have been extracted and calculated using material parameters available from literature. The attenuation of guided optical waves along the propagation track in AlxGa1-xN layers has been measured using the CCD imaging technique. The attenuation dependence on the mode order and layer thickness has been studied. Our results show that the properties of AlxGa1-xN that determine surface acoustic wave and guided optical wave propagation are similar to the properties of GaN films within a relatively wide range of x up to x =0.36.

Single Degree of Freedom Passive Bilateral Hydraulic Teleoperation Using a Passified Two-Stage Servo-Valve

Passive machines possess the inherent property that they can interact stably with other passive systems. A problem with applying the concept of passivity to ensure interaction stability of hydraulic machines is that the latter are not intrinsically passive. In previous work, a passifying control was developed to ensure that a single-stage directional control valve behaves like a passive two-port device. The passified valve was used in passive teleoperation of a hydraulic actuator. Unfortunately, single-stage valves are limiting in their flow rate and bandwidth capabilities which can be remedied using multistage valves. In this paper, we first review a passifying control which ensures that a non-passive two-stage pressure control servo-valve behaves like a nearly-passive two-port device. A teleoperation controller that uses the passified two-stage valve is then developed to ensure 1-DOF coordinated motion of the passive hydraulic actuator system (slave) and a force:feedback joystick (master). The control also guarantees the passivity property of the teleoperation system.

Modeling ferroelectric capacitors for memory applications

The ferroelectric capacitor model is the foundation for accurate simulation of ferroelectric hysteresis loops and minor loops, transitions between the loops under arbitrary voltage patterns, transient responses of ferroelectric capacitors to short voltage pulses with widths in the nano-second range, and temperature behaviors of ferroelectric capacitors. The simulation speed is the same as that for a typical nonlinear capacitor. To the circuit designers, a ferroelectric capacitor is represented as a two-port device like a capacitor. The parameters are extracted easily and reliably by curve fitting the measured hysteresis loops. The model is applicable to fast circuit simulations for large ferroelectric memory designs.

A comparison among different setups for measuring on-wafer integrated inductors in RF applications

This paper presents a comparison to study the most suitable setup for measuring an integrated inductor using a vector network analyzer. It assumes that the inductor will be modeled with the /spl Pi/ model, the lumped equivalent circuit most often used by designers. We have demonstrated that measuring an inductor with a one-port analyzer is not suitable for an accurate characterization of this type of device. Instead, we propose that the best method is measuring the inductor placed in series between the two ports of the analyzer. The method presented can be extrapolated to the study of how to measure other two-port devices in which the lumped equivalent circuit used to characterize its performance is previously known.

Advanced interferometric phase and amplitude noise measurements

The measurement of the close-to-the-carrier noise of two-port radio frequency and microwave devices is a relevant issue in time and frequency metrology and in some fields of electronics, physics, and optics. While phase noise is the main concern, amplitude noise is often of interest. Presently the highest sensitivity is achieved with the interferometric method, that consists of the amplification and synchronous detection of the noise sidebands after suppressing the carrier by vector subtraction of an equal signal. A substantial progress in understanding the flicker noise mechanism of the interferometer results in new schemes that improve by 20–30 dB the sensitivity at low Fourier frequencies. These schemes, based on two or three nested interferometers and vector detection of noise, also feature closed-loop carrier suppression control, simplified calibration, and intrinsically high immunity to mechanical vibrations. This article provides the complete theory and detailed design criteria, and reports on the implementation of a prototype working at the carrier frequency of 100 MHz. In real-time measurements, a background noise of −175 to −180 dBrad2/Hz has been obtained at f=1 Hz off the carrier; the white noise floor is limited by the thermal energy kBT0 referred to the carrier power P0 and by the noise figure of an amplifier. Exploiting correlation and averaging in similar conditions, the sensitivity exceeds −185 dBrad2/Hz at f=1 Hz; the white noise floor is limited by thermal uniformity rather than by the absolute temperature. A residual noise of −203 dBrad2/Hz at f=250 Hz off the carrier has been obtained, while the ultimate noise floor is still limited by the averaging capability of the correlator. This is equivalent to a signal-to-noise (S/N) ratio of 2×1020 with a frequency spacing of 2.5×10−6. All these results have been obtained in a relatively unclean electromagnetic environment, and without using a shielded chamber. Implementation and experiments at that sensitivity level require skill and tricks, for which a great effort is spent in the article. Applications include the measurement of the properties of materials and the observation of weak flicker-type physical phenomena, out of reach for other instruments. As an example, we measured the flicker noise of a by-step attenuator (−171 dBrad2/Hz at f=1 Hz) and of the ferrite noise of a reactive power divider (−173.7 dBrad2/Hz at f=1 Hz) without need of correlation. In addition, the real-time measurements can be exploited for the dynamical noise correction of ultrastable oscillators.

The energy conservation law for optical two-port devices

The relationship between the parameters of quadripoles (mirrors, for example) ensuring the fulfillment of the energy conservation law are considered. Apart from the standard balance of transmitted, reflected, and absorbed energy in a traveling light wave, some additional conditions imposed on the amplitudes and phases of the coefficients of the scattering matrix should be met. These conditions have been found by considering the light reflection from the Fabry-Perot interferometer with a quadripole used as one of the mirrors. An additional condition involves the Hamy phase parameter ϑ=Ψ1+Ψ2-2Φ, where Ψ1, Ψ2 are the phases of the reflected light, and Φ is the phase of the transmitted light. Another condition relates the amplitudes of the reflected light R 1 1/2 , R 2 1/2 , and the transmitted light T 1/2. At a certain combination of parameters the quadripole becomes unrealizable physically. Specific examples are considered.

Toward Safe and Human Friendly Hydraulics: The Passive Valve

Hydraulic systems, as power sources and transmissions, offer many advantages over electromechanical or purely mechanical counterparts in terms of power density, flexibility, and portability. Many hydraulic systems require touching and contacting the physical environments; and many of these systems are directly controlled by humans. If hydraulic systems are passive, they would be both safer to interact with, and easier for humans to control. In this paper, it is shown that a critical hydraulic component, the directional control valve, is not passive. However, the directional valve, as a one-port or a two-port device can become passive if appropriate spool valve dynamics are imposed. Methods to passify the valve for both first-order and second-order spool dynamics are considered. In the case of second-order spool dynamics, a passive method that relies on hardware modification, and an active feedback method, are proposed. [S0022-0434(00)01803-7]

Intermodulation measurements in Nb superconducting microstrip resonators

The issue of intermodulation distortion in superconducting devices for rf and microwave applications is discussed. The classical frequency conversion theory for nonlinear two-port devices in the small signal limit is shown to apply to microstrip resonators regardless of their geometry and material. Two tone, third order intermodulation measurements allow more sensitive detection of nonlinearity compared to surface impedance measurements, provided a low noise, spurious free experimental setup is adopted. Measurements carried out on high quality Nb meanderline microstrip resonators show that at very low power level nonlinearity is dominated by intrinsic device properties. Film defects start to play a predominant role above a critical power level that strongly depends on the defect’s nature.

A review of wireless SAW sensors

Wireless measurement systems with passive surface acoustic wave (SAW) sensors offer new and exciting perspectives for remote monitoring and control of moving parts, even in harsh environments. This review paper gives a comprehensive survey of the present state of the measurement systems and should help a designer to find the parameters required to achieve a specified accuracy or uncertainty of measurement. Delay lines and resonators have been used, and two principles have been employed: SAW one-port devices that are directly affected by the measurand and SAW two-port devices that are electrically loaded by a conventional sensor and, therefore, indirectly affected by the measurand. For radio frequency (RF) interrogation, time domain sampling (TDS) and frequency domain sampling (FDS) have been investigated theoretically and experimentally; the methods of measurement are described. For an evaluation of the effects caused by the radio interrogation, we discuss the errors caused by noise, interference, bandwidth, manufacturing, and hardware tuning. The system parameters, distance range, and measurement uncertainty are given numerically for actual applications. Combinations of SAW sensors and special signal processing techniques to enhance accuracy, dynamic range, read out distance, and measurement repetition rate (measurement bandwidth) are presented. In conclusion, an overview of SAW sensor applications is given.

Calibrating network analyzers using a through and a line or a through and a match for transmission parameter measurement

This letter presents a general partial two-port calibration scheme for transmission parameter measurement. Calibrating network analyzers using a through and a line or a through and a match are two applications under the scheme. The second application, which is a new result, is validated experimentally by a comparison with the first one recently discussed. Both applications are useful in characterizing two-port devices whose reflection parameters are of little interest. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 20: 434–436, 1999.

An enhanced on-wafer millimeter-wave noise parameter measurement system

A novel on-wafer resistive noise source, useful for noise characterization of microwave devices with the cold noise power measurement technique, is described. The noise source enhances measurement accuracy by providing a calibrated noise temperature directly at the device reference plane. A procedure for determining the excess noise ratio of the noise source is presented and validated up to 40 GHz. The noise source is employed in an on-wafer measurement system, allowing the noise parameters of two-port devices to be extracted. Following a description of the apparatus and measurement procedure, an example of a high-electron-mobility transistor noise parameter measurement at millimeter-wave frequencies is presented.

System configurations for nine-port network analyser employing symmetrical five-port junctions

A nine-port network analyser that requires only six (instead of eight or ten) power sensors to obtain the unknown scattering coefficients of a two-port device is proposed. Hardware imperfections will naturally affect the performance of this instrument. Monte Carlo simulations have been conducted in order to evaluate the deleterious effects due to the residual mismatches of the constituent components within the nine-port system. The results suggest that improvements in instrumentation accuracy may be achieved simply by modifying the system's overall configuration.

Dielectric plug-loaded two-port transmission line measurement technique for dielectric property characterization of granular and liquid materials

There are numerous dielectric property characterization techniques available in the microwave regime each with its own uniqueness, advantages and disadvantages. The two-port completely-filled waveguide (transmission line) technique is a robust measurement approach which is well suited for solid dielectric materials. In this case, the dielectric material can be relatively easily machined to fit inside the waveguide and the subsequent measurement of the scattering parameters of this two-port device renders the dielectric properties of the material filling the waveguide. However, this technique is not well suited for measuring the dielectric properties of granular and liquid materials. These materials are used in the production of various composites which are increasingly replacing the use of metals in many environments. If this technique is directly applied to these types of materials, several approximations either in the measurement apparatus or the formulation must be made. To overcome this problem, this paper describes a modification to this measurement technique utilizing two dielectric plugs which are used to house the granular or the liquid dielectric material. In this approach no approximation to the measurement apparatus is made while the presence of the plugs are fully accounted for in the derivations. Using this technique, the dielectric properties of cement powder, corn oil, antifreeze solution and tap water, constituting low- and high-loss dielectric materials (granular and liquid) were measured. In addition, the important issue of measurement uncertainty associated with this technique is also fully addressed. The issue of optimal choice of various measurement parameters is also discussed as it relates to the measurement uncertainty.

Simple, accurate method forcharacterising two-port deviceswith small reflections

A simple yet accurate method for characterising a two-port device with small reflections using a network analyser is presented. The method only requires two measurements, corresponding to through and device connections, to remove the influence of systematic errors on the transmission parameters of the device. Experimental results support the method.

Magnetically-excited flexural plate wave resonator

A flexural plate wave (FPW) resonator was constructed by patterning current lines on a silicon nitride membrane suspended on a rectangular silicon frame. Eigenmodes of the rectangular membrane were excited using Lorentz forces generated between alternating surface currents and a static in-plane magnetic field. The magnetic field strength required for these devices can be achieved with small permanent magnets (/spl ap/1 cm/sup 3/). Preferential coupling to a particular membrane mode was achieved by positioning current lines along longitudinal mode antinodes. An equivalent-circuit model was derived that characterizes the input impedance of a one-port device and the transmission response of a two-port device over a range of frequencies near a single membrane resonance. Experiments were performed to characterize the effects of varying magnetic field, ambient gas, gas pressure, and input power. To our knowledge, this is the first experimental demonstration of a resonant FPW device.

Flexural plate wave resonator excited with Lorentz forces

A flexural plate wave resonator was constructed by patterning current lines on a silicon nitride membrane suspended on a rectangular silicon frame. Eigenmodes of the rectangular membrane were excited using Lorentz forces generated between alternating surface currents and a static in-plane magnetic field. Preferential coupling to a particular membrane mode was achieved by positioning current lines along longitudinal mode antinodes. An equivalent-circuit model was derived which characterizes the input impedance of a one-port device and the transmission response of a two-port device over a range of frequencies near a single membrane resonance. Experiments were performed to characterize the device’s response to changes in dc magnetic field strength, ambient gas composition, gas pressure, and input power.

Synthesizing arbitrary driving-point and transfer characteristics

The property of any two-terminal resistive device is characterized by its driving-point (DP) characteristic, and any two-port resistive device with zero input current and a load-independent output voltage is described by its transfer characteristic (TC). Synthesizing a two-port device with a prescribed transfer characteristic is usually easier than synthesizing a two-terminal device with a prescribed driving-point characteristic. In this paper we propose an approach to synthesize a driving-point characteristic of a two-terminal device from the transfer characteristic of a two-port device, so that the resulting DP plot of the two-terminal device is exactly the same as the TC plot of the two-port device. We also illustrate the use of digital circuitry to synthesize arbitrary transfer characteristics. This technique will benefit the design and analysis of complex nonlinear electronic circuits and systems. A variety of characteristics synthesized using this approach are presented.

A simple error correction method for two-port transmission parameter measurement

This letter presents a simple error correction method for two-port transmission parameter measurement. The method requires measuring only two nonreflecting transmission lines instead of a complete set of calibration standards (at least three) for error correction, it does not need an explicit solution of error coefficients. These two features make it simpler than any other methods. Error-corrected measurement results of a CPW discontinuity using the new method and the TRL method are in good agreement. The new method is useful in characterizing well-matched two-port devices or those whose reflection parameters are of little interest.

All-optical Mach-Zehnder wavelength converter with monolithically integrated DFB probe source

The first interferometric wavelength converter with an integrated continuous-wave (CW) probe source is presented. The two-port device operates independent of polarization for a broad range of input wavelengths. The input dynamic range is enhanced by an integrated input preamplifier. Input powers as low as -5.4 dBm in the fiber are converted with penalties as low as 0.6 dB at a bit rate of 2.5 Gb/s. The device is shown to operate with the same low penalty for same-wavelength operation as well. The chirp parameter /spl alpha/ is measured to be 2 for wavelength conversion. No chirp is added to the input signal for same-wavelength operation.