Louis Jallet

A new robust method for six-port reflectometer calibration

A new robust method for finding the parameters of Engens six-port-to-four-port reduction algorithm for six-port reflectometer calibration has been developed. Like other previously published methods, it uses a minimum of five loads with an unknown but constant absolute value of the reflection coefficient and unknown but well-distributed phases. However, the quality of the parameter estimates is improved, especially in noisy environments, by efficiently eliminating cases in which these earlier methods may become ill-conditioned. The new method has been used successfully to calibrate a newly developed six-port reflectometer in GaAs MMIC technology working between 1.3 GHz and 3.0 GHz.

Automated characterization of HF power transistors by source-pull and multiharmonic load-pull measurements based on six-port techniques

An original measurement system for nonlinear microwave power-transistor characterization using six-port reflectometers is presented. It allows independent active tuning of the output impedances at f/sub 0/ and 2f/sub 0/ (multiharmonic load-pull) and variation of the source impedance at the input port at f/sub 0/ (source-pull). An appropriate search algorithm enables automatic optimization of the output impedances and leads to fast user-friendly operation of the system. Experimental results are shown for a commercial GaAs MESFET power transistor at f/sub 0/=2 GHz.

New structure for a six-port reflectometer in monolithic microwave integrated-circuit technology

This paper presents a new structure for a six-port reflectometer which due to its simplicity can be implemented very easily in monolithic microwave integrated-circuit (MMIC) technology. It uses nonmatched diode detectors with a high input impedance which are placed around a phase shifter in conjunction with a power divider for the reference detector. The circuit has been fabricated using the F20 GaAs process of the GEC-Marconi foundry and operates between 1.3 GHz and 3.0 GHz.

RF power detector using a silicon MOSFET

This paper presents a novel approach for RF power measurements using a silicon MOSFET. It describes linear and nonlinear models of the RF MOSFET for results prediction. It shows a thorough comparison between predicted and measured results. The detector demonstrates a better sensitivity than biased Schottky diode detectors that we have measured.

Noise and power optimization of a MMIC quasi-circulator

This paper first sums up the power and noise limits of various types of active circulators and quasi-circulators. It then presents the design and measured performances of a narrow-band quasi-circulator module tailored for use in a transmit/receive (T/R) module. Its design implements an active power divider and a combiner, a method to calculate the minimum noise figure is presented for this circuit. At 4 GHz, the device demonstrates a noise figure of 5.5 dB and an output power of 18 dBm with associated gains of 4 and 7.6 dB for the receive and transmit path, respectively. The third-order intercept point (IP3) is equal to 25.6 dBm for the transmit path.

Accuracy analysis for six-port automated network analyzers

One of the assumptions made in six-port automated network analyzer (ANA) theory is that the reflection coefficient of the power detectors does not change with incident power level. This is not generally the case if diode detectors are used. Consequently, uncertainties in the measurement of the reflection coefficient of the unknown load appear because the calibration constants vary due to the variation of the detector reflection coefficients with power. Measurements of the variations of diode input impedance using commercial ANAs are used in a computer simulation to estimate their uncertainties. >

An active millimeter load-pull measurement system using two six-port reflectometers operating in the W-frequency band

An active load-pull measurement system using two six-port reflectometers operating in the W-frequency band is demonstrated. Ninety loads over the whole Smith chart have been synthesized and measured by both reflectometers. The maximum deviation between both measurement data is 0.02 for the magnitude and 3/spl deg/ for the phase of the reflection coefficient of the 90 loads. The constant power gain circles of a PHEMT operating at 89 GHz are shown and compared with those calculated from its S/sub ij/ scattering parameters. The deviation between the radii of circles is less than 0.03.

MMIC quasi-circulator with low noise and medium power

This paper presents the design and the measured performances of a narrow band quasi-circulator module. Its design implements active divider and combiner. The device demonstrates a noise figure of 5.5 dB and an output power of 18 dBm with associated gains of 4 dB and 7.6 dB for the receive and transmit path, respectively.

Conception et résultats de mesure d’un analyseur de réseaux à six accès dans la bande de fréquence 1-18 GHz

RésuméL’analyseur de réseaux à six accès permet de déterminer la matrice S de répartition de tout circuit linéaire. Après avoir présenté les principes de cette mesure, les performances du circuit hyperfréquence associé au banc de mesure sont décrites dans la bande de fréquence 1-18 GHz- L’étalonnage de l’appareil, basé sur la mesure de trois dispositifs (1 court-circuit mobile, 1 ligne de propagation, 1 atténuateur) et la linéarisation de la détection de puissance par des diodes Shottky sont décrites dans la troisième partie. Enfin, les résultats de la mesure de diverses charges sont comparés à ceux obtenus par un analyseur de réseau du commerce.AbstractThe six port network analyzer measures the scattering matrix S of any linear two port. After discussion of the measurement principle, the performance of the microwave circuit associated with the test bench is described in the frequency band 1-18 GHz. The six port calibration, based on the measurement of three devices (1 sliding short, 1 propagation line, 1 attenuator), and the linearization of the Shottky diode detectors are described in the third part. Finally, experimental results are shown and they are compared with those obtained using a commercial network analyzer.

Réalisation ďun Réflectomètre a Six Accès Dans la Bande de Fréquences Millimétriques W (75-110 GHz)

RésuméCet article présente un réflectomètre à six accès en bande W (75-110 GHz). La mesure de la puissance est effectuée par des diodes Schottky fonctionnant dans un mode de détection en courant alternatif. Une procédure de linéarisation est utilisée afin ď améliorer ľ exactitude des mesures. Ľ étalonnage du banc de mesure est effectué avec deux charges. Enfin, les résultats expérimentaux sont comparés avec ceux obtenus à ľ aide ď autres analyseurs de réseau dans cette bande de fréquences.AbstractThis paper presents a six-port reflectometer in the W frequency band (75-110 GHz). Schottky diodes, operating in AC detection mode, are used as power detectors. A linearization procedure is used to improve the measurement accuracy. The six-port calibration is performed with two standards. Finally, the experimental results are compared with those obtained with other network analyzers in this frequency band.