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ARFTG Conference Digest, Spring 2003. 61st

Date 13-13 June 2003

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Displaying Results 1 - 25 of 25
  • 61st ARFTG Conference Digest Spring 2003 [Automatic RF Techniques Group] [front matter]

    Page(s): 0_1 - V
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    Freely Available from IEEE
  • A calibration procedure for on-wafer differential load-pull measurements

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB) |  | HTML iconHTML  

    This paper presents a calibration technique for on-wafer diflerential load-pull measurements. The described calibration procedure makes use of a standard GS/SG calibration substrate only. The calibration accuracy achieved is verified through various independent standards measurement. View full abstract»

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  • Accurate broadband on-wafer SOLT calibrations with complex load and thru models

    Page(s): 5 - 10
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (317 KB) |  | HTML iconHTML  

    An improved vector network analyzer calibration approach is demonstrated that utilizes planar lumped short-open-load-thru (SOLT) standards and achieves accuracy comparable to TRL at high frequency, without the commonly occurring errors in TRL at low frequency. The approach relies on complex loadmodels for CPW and microsttip loads that are not currently available in VNA fmware. A non-ideal (lossy) model for the thru line standard is used to enhance results for calibrations involving non-zero length thru lines. GaAs microstrip and CPW substrates were used for the purpose of experimental verification. It is shown that the RF performance changes due to GaAs load fabrication variation can be addressed by "calibrating" or adjusting the load model with the measured DC resistance for a particular load. View full abstract»

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  • Application of weighted least squares to OSL vector error correction

    Page(s): 11 - 21
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (338 KB) |  | HTML iconHTML  

    The use of least squares has been beneficial in providing more accurate one-port calibrations. Commercially available ECAL units have taken advantage of this method. A more generalized application of a least squares method, the weighted least squares method provides benefit when the models for the calibration standards are not all trusted equally. The use of the weighted least squares provides a method of discounting the effect of calibration standards as the model accuracy degrades instead of abruptly dropping the use of the standard outside of a specified frequency range avoiding discontinuities in subsequent measurements. A detailed view a 1.85 μm calibration kit demonstrates the improved results possible using a weighted least squares method. The paper includes the description of a proximity function that enhances the results when the response of two or more standards begin to cluster. Additional enhancements due to databased models over traditional polynomial models is also presented. View full abstract»

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  • A low cost implementation of automated RF test of a LNA

    Page(s): 23 - 26
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (390 KB) |  | HTML iconHTML  

    A low cost, automated, high volume RF test setup for a low-noise amplifier (LNA) was realized. A standard production DC test system and handler were modified with the addition of a standard vector network analyzer to measure sparameters at 1.9 GHz. Motivation for a low cost RF test methodology came from the need to minimize production costs of the high volume MBC13916 LNA. The solution achieved accurate and reliable low cost RF testing. An in-depth analysis of the test data was performed to correlate the data to the existing RF test setup and to verify the impact on the final cost per part of performing RF test. View full abstract»

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  • High-temperature probe station for use in microwave device characterization through 500°C

    Page(s): 27 - 35
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (827 KB) |  | HTML iconHTML  

    A high-temperature measurement system capable of performing on-wafer microwave testing of semiconductor devices has been developed. This high temperature probe station can characterize active and passive devices and circuits at temperatures ranging from room temperature to above 5OO°C. The heating system uses a ceramic heater mounted on an insulating block of NASA shuttle tile material. The temperature is adjusted by a simple graphical computer interface and is automatically controlled by the sohare-based feedback loop. The system is used with a Hewlett-Packard 8510C Network Analyzer to measure scattering parameters over a frequency range of 1 to 50 GHz. The microwave probes, cables, and inspection microscope are all shielded to protect from heat damage. The high temperature probe station has been successfully used to characterize gold transmission lines on silicon carbide at temperatures up to 540°C. View full abstract»

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  • Differential de-embedding methodology for on-board CPU socket measurements

    Page(s): 37 - 43
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (579 KB) |  | HTML iconHTML  

    This paper describes a methodology that accurately deembeds the test structure from the socket and demonstrates valid results up to 15 GHZ. The test structure mnsists of a probe launch and microstrip line to access the socket at the PCB side, and a probe launch and plated through hole (PTH) via on a top test interface board to au%ss the top of the socket. In order to characterize the pure socket performance excluding the performance deterioration from the PTH vias, those launchers are to be deembedded. The deembedding methods described in this work are based on 2- and 4-port ABCD parameters. The methods were extensively applied to various CPU sockets in order to extract the singleended and differential socket S-parameter data. View full abstract»

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  • Waveguide technique for ferroelectric bulk and film microwave study

    Page(s): 45 - 51
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (550 KB) |  | HTML iconHTML  

    Non-resonant waveguide method is presented to study materials with large dielectric constant ϵ. The enhanced method is based on network analyzer use and combines benefits of all known techniques. An additional custom calibration procedure is employed. Gathering redundant data of scattering parameter frequency dependence accompanied with curve fitting data processing is implemented. To increase microwave penetration into studied large-ϵ specimen, a low-ϵ matching dielectric plate is adapted. The influence of air gaps between specimen and waveguide is studied and errors eliminated. Higher-order mode propagation conditions analysis is considered. Waveguide partial tilling is studied and applied as a new electrode-less technique for ferroelectric thin film study. Experimental results of reference materials investigation are presented. View full abstract»

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  • Spectrally pure excitation signals: Only a dream?

    Page(s): 53 - 63
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (447 KB) |  | HTML iconHTML  

    Multi-tone excitation signals become increasingly important for test and measurement purposes. However, the signal sources used to create such multitone signals are not perfect and often create unwanted spectral contributions. This paper presents a method to create spectrally pure signals, such as two-tones or multitones, using signal sources based on arbitrary waveform generators (AWG). Only amplitude information is needed, so that a spectrum analyzer can be used to perform all necessary measurements. Unwanted spectral lines are suppressed, independent of their exact origin. This allows to apply a testsignal with the correct spectral content to the device under test, even if the signal source is not perfect or external disturbances are present. Measurements on an RF amplifier show the capabilities of the method. View full abstract»

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  • Use of multisine signals for efficient behavioural modelling of RF circuits with short-memory effects

    Page(s): 65 - 72
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (459 KB) |  | HTML iconHTML  

    Behavioral models for RF devices are often based on single-tone data. However, this ype of excitation is not representative of the digital modulation to which many RF devices are subjected in teleconimunication systems. In this work, we show that the use of multisine excitation renders the modelling more eficientfi.om both the experiment design and the data handling points of view, without loss of accuracy. View full abstract»

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  • Phase detrending for measured multisine signals

    Page(s): 73 - 83
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (521 KB) |  | HTML iconHTML  

    We develop a method to detrend the phases of measured multisine signals. We find a time reference that removes the linear component of the measured phases and aligns them, within a precision specified by the user, to their expected values. An initial guess is provided by a closed-form expression. We then find the global minimum of a user-specified error function. The simple postprocessing algorithm is general and can be implemented in many software packages. View full abstract»

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  • Automated measurement of intermodulation tables for mixers

    Page(s): 85 - 95
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (645 KB) |  | HTML iconHTML  

    This paper discusses an automated measurement procedure for intermodulation products of mixers. The measurement results are typically stored in an intermodulation table (IMT) file for use in computer-aided engineering (CAE) simulators. The new procedure was developed using a dedicated 40 GHz frequency translation device test system from Anritsu (ME7810A). Calibration, utilizing a power meter, improves the accuracy of spectrum analyzer amplitude measurements of the various frequency components and accounts for the frequency responses of all cable and connector frequency responses. The ability to automate the calibration and measurement process for IMT files greatly facilitates building a data set that can be used for accurate prediction of the performance of mixers. The measurement results provide a multi-dimensional view of the performance of the mixers. Examples are shown for a ZEM4300 mixer from Mini-Circuits. View full abstract»

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  • Time-domain characterization of nonlinear operation of an AlGaN/GaN HEMT

    Page(s): 97 - 102
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (258 KB) |  | HTML iconHTML  

    A method to extract input and output voltage and current time-domain wavefroms has been applied to characterize operation of a discrete high-power AIGaN/GaN HEMT under different bias and source and load impedance conditions. It provides valuable insight into how various device parameters, such as knee voltage, DC-to- RF dispersion and nonlinear capacitances affect large-signal microwave performance. Time domain waveforms will be presented. View full abstract»

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  • Uncertainty and design budgets applied to error vector magnitude (EVM) for digital modulation systems

    Page(s): 103 - 109
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (468 KB) |  | HTML iconHTML  

    EVM is a key metric for RF components and subsystems in most digital modulation systems. Understanding the way in which different distortion mechanisms contribute to the overall EVM is the key to determining how to construct a system budget for EVM. Not only must each block in a transceiver chain have a sufficiently small EVM, test equipment uncertainties are also a significant proportion of such a budget. This leads to the question of bow EWI contributions and uncertainties add, and how to ensure that an indicated result is within specification. Some contributions add coherently - to raise or (possibly) lower the composite value; and some add randomly, in a noise-like fashion, such that the EVM increases according to an RSS additiou. This paper investigates both random and coherent distortion effects, and demonstrates how to treat each type correctly. EMM examples for GSM/EDGE, WCDMA and 802.11a are presented. View full abstract»

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  • On the implementation of AM/AM AM/PM behavioral models in system level simulation

    Page(s): 111 - 115
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (198 KB) |  | HTML iconHTML  

    The use of nonlinear device behavioral models offers an economical way of simulating the performance of complex communication systems. A concrete method for implementing the AM/AM AM/PM behavioral model in system level simulation using ADS is developed. This method seamlessly tansfers the data from the circuit level simulation to system level simulation, where the AM/AM AM/PM model is automatically built. The methodology is extendible for use in other software packages or between different software packages. View full abstract»

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  • An experimental low-voltage I-band oscillator assembled with only five SMD-components

    Page(s): 117 - 124
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (586 KB) |  | HTML iconHTML  

    An easy to assemble experimental I-band oscillator which uses only five SMDcomponents is described. The resonant circuit is built up by two microstrip lines and an interdigital capacitor etched on a common FR4 substrate, respectively. Only two junction field-effect transistors (JFETs), two capacitors and one resistor are necessary to build up this low-cost oscillator. With a supply voltage of 3.0 V, an output power of more than 1 mW is achieved at an operating frequency of 9.24 GHz. The measured suppression of the harmonics is better than 55 dBc. The realised oscillator has small geometrical dimensions and is very well suited to be manufactured as a monolithic microwave integrated circuit (MMIC), too. Integrating an additional tuning diode Will enable the oscillator to serve as a low-voltage VCO in a smallband PLL circuit. View full abstract»

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  • Role of spectral purity of down-converting local oscillator in the evaluation of noise figure of microwave amplifiers

    Page(s): 125 - 132
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (376 KB) |  | HTML iconHTML  

    The importance of spectral purity of down-converting local oscillator in the accurate measurement of noise figure of microwave DUTs has been discussed. The errors in the noise figure measurements resulting due to spurious frequency components of the down-converting local oscillator have been analyzed. Acceptable spurious levels in the local oscillator spectrum for error-free noise figure measurements has been proposed View full abstract»

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  • Minimizing distortions in the time-domain measurement of microwave communications signals

    Page(s): 133 - 141
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (420 KB) |  | HTML iconHTML  

    We present a new method to minimize inaccuracies in time-domain measurements of microwave communications signals. The signal measurements are accomplished by converting the signal to baseband where accurate instrumentation is available. The baseband signal is composed of in-phase (I) and quadrature (Q) components. The I and Q waveform measurements differ by a π/2 phase shift in the local oscillator used in the downconversion. Any I/Q imbalances may be detected and reduced by requiring the complex baseband signal to be invariant (apart from a rotation in the complex plane) with respect to the local oscillator phase. The complex baseband signal is measured twice, where the local oscillator (LO) phase is 0, and π/2 for the first signal measurement, and θ, and θ + π/2 for the second. Any I/Q imbalances and baseband nonlinearities are indicated by differences between the two measured signals. An LO phase shift of θ = π/4 + mπ/2, where m is an integer, is optimum for error detection. The errors may be reduced by averaging the measurements and by optimization of the measurement system. Errors caused by I/Q imbalances have been reduced to an error-to-signal power ratio of less than -56 dB. This accuracy is sufficient for essentially any communications system modeling applications. View full abstract»

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  • A low cost temperature-controlled chuck for a cascade probestation

    Page(s): 143 - 146
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (490 KB) |  | HTML iconHTML  

    It is getting increasingly important to be able to characterize the temperature behavior of transistors and circuits. This paper describes construction of a low cost temperature controlled chuck for this purpose. The motivation for this in-house design is that equipment of this kind is expensive. A simple inexpensive design with acceptable performance can be constructed with standard circuits. The goal for the prototype is to be able to regulate the temperature between 0°C and 80°C ±0.5°C with a distribution error over the top plate of maximum ±0.5°C in the central area. The performance of the temperaturecontrolled chuck is evaluated and it displays behavior within the specified goals. View full abstract»

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  • Calculation and accurate measurement of capacitance of electrically small axi-symmetric microstructures near a probe tip

    Page(s): 147 - 156
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (394 KB) |  | HTML iconHTML  

    An efficient calculation method that uses semi closed-form solutions of axisymmetric metallic sub-sections to numerically calculate the capacitance of a metallic probe over stratified dielectric substrates or metallic samples is developed and discussed. The current continuity equation was first used to obtain charge densities at the structure's surface. The capacitance matrix that uses gap and permittivity (CGP) as indexes for specific tip was then numerically estimated using this method. CCP matrix enabled noncontact simultaneous topography and permittivity mapping using a single microwave measurement. This method was subsequently used to calculate the capacitance of spherical and conical tips commonly used in local scanning probe microscopy. To evaluate the accuracy of the this method, the load impedance change of the above structures were measured and compared to their numerical values. The load impedance of the probe tip was experimentally determined from the input impedance of a λ/2 microstrip resonator at 1 GHz The model of the measurement apparatus and a calibration procedure were also developed. The experimental data agreed with the numerical results quite well. Moreover, the experiments also showed that the simple λ/2 microstrip resonator has an excellent capacitance resolution nearing 1.96x10-18 at 1 GHz using a BiCMOS I/Q detector. View full abstract»

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  • An automatic program suitable for on-wafer characterization and statistic analysis of microwave devices

    Page(s): 157 - 161
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (844 KB) |  | HTML iconHTML  

    A macro program based on Agilent IC-CAP software is developed for on-wafer characterization and statistic analysis of microwave devices. With the perfect combination of Cascade Nucleus software and the IC-CAP GUI (Graphical User Interface) technique in our program, multi-die, multi-type devices characterization and statistic analysis can be easily achieved to get the quantification information that is very important for device engineers, modeling engineers and circuit designers. Furthermore, automatic moving and probing can dramatically improve the measurement accuracy by eliminate the measurement error due to probing condition variation. View full abstract»

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  • Development and application of a 1/f transistor noise measurement technique

    Page(s): 163 - 170
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (500 KB) |  | HTML iconHTML  

    This paper introduces and addresses several subtle aspects to the performance of 1/f or flicker noise measurements on microwave transistors. A straightforward measurement system can be assembled using a dynamic signal analyzer, vector signal analyzer, or spectrum analyzer, however, there are a number of potential pitfalls that will prevent accurate measurements. These include bias supply noise, extemal electromagnetic interference (including that from your own bench!), device instability, as well as the dependence of the results on the resistive elements comprising the bias supply filtering or voltage divider networks. This work shows that good results can be achieved with a relatively simple setup after systematically eliminating the influence of these extemal factors on the 1/f noise measurements of interest. A Labview program was written to facilitate the data acquisition and data manipulation for the simple lowcost setup utilized in this work. Example measurements are shown for microwave MESFET. BJT, and a SiGe HBT to illustrate the techniques. View full abstract»

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  • Evaluation of coaxial V-connector LRL impedance standards for the 65 GHz vector network analyzer

    Page(s): 171 - 177
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (345 KB) |  | HTML iconHTML  

    This paper presents the results of an investigation of V-connector (1.85 mm) LRL impedance standards used in calibrating a 65 GHz vector network analyzer (VNA). Coaxial V-connector impedance standards are also denoted as the 1.85 mm connector in the IEEE 287-2001 draft. Transmission lines are the primary impedance standards for microwave measurements. Current traceable standards for coaxial measurements are available in frequency ranges below 50 GHz. Measurement needs in the fields of optoelectronic and high speed microelectronic industries have driven the requirements of traceability to 65 GHz. Therefore, we have conducted an evaluation of LRL transmission lines as our reference standards. Two sets of these lines were built in house. They were evaluated both mechanically and electrically. The electrical performance of an LRL airline calibration compared with a sliding load calibration will be reported. View full abstract»

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  • A method for computing the characteristic impedance of transmission lines using the wave cascade matrix formalism

    Page(s): 179 - 185
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (252 KB) |  | HTML iconHTML  

    This work deals with the characterization of the line impedance of uniform transmission lines. Using the Wave Cascade Matrix representation (WCM) of a uniform transmission line as reported by J.A. Reynoso-Hernandez (2003), a new method for determining the line impedance is presented. The method can be used fur any kind of transmission line. To demonstrate the usefulness of the proposed method, the line impedance of coplanar waveguides (CPWs), using SRO20 and SiO2 as the passivation layer is evaluated both in dark conditions and when illuminated by a visible laser. View full abstract»

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  • Design strategy of custom switch relay box

    Page(s): 188 - 196
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (404 KB) |  | HTML iconHTML  

    Design of custom solution for switch relay box is complex matter that depends on many items. What can be important for design and what problems should be solved during the design are considered. Also, procedure and strategy was explored. Number of used switches depends on number of ports and number of measurements. View full abstract»

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