Walid S. El-Deeb

Small-signal, complex distortion and waveform measurement system for multiport microwave devices

This paper presented a general-purpose multiport measurement system and calibration algorithm for the characterizations of N-port microwave devices. The system is built around the micro wave transition analyzer as a multi-harmonic receiver from DC to 40 GHz, which provides the system with the scope capability for time domain measurements and the vector network analyzer capabilities for frequency-domain measurements. The developed system has the capability of measuring the S-parameters of linear microwave circuits as well as the AM-AM and AM-PM conversions for nonlinear microwave devices in single-step measurements, without any need for reconnection or change in the calibration technique or meas urement setup. The system can accurately quantify the impact of crosstalk on the performance of the multiport nonlinear microwave systems in terms of power efficiency and signal distortion. The proposed calibration algorithm for waveform measurements utilizes a standard signal frequency generator and does not rely on the use of a multi-harmonic generator to calculate the error box parameters at the fundamental and harmonic frequencies. The algorithm is also applicable to any multi-harmonic phase-locked receiver based measurement system. Finally, it has been demonstrated that the measurement system is capable of performing waveform engineering measurements. The comparison of waveforms obtained in 50 Ω and non-50 Ω impedance environments using the developed system and standard commercial scopes shows good agreement. This enhances confidence in the measurement data obtained from the developed measurement system.

A Multiport Measurement System for Complex Distortion Measurements of Nonlinear Microwave Systems

An effective multiport measurement system for the characterization of N-port nonlinear microwave devices is proposed. The proposed measurement system has the capability of measuring the S-parameters of linear microwave circuits and the amplitude-modulation-to-amplitude-modulation (AM/AM) and amplitude-modulation-to-phase-modulation (AM/PM) conversions for fundamental and harmonic frequencies for nonlinear microwave devices on single-step measurement without any need for reconnection or change in the calibration technique or measurement setup. It is found suitable that the proposed system can accurately quantify the impact of crosstalk on the performance of multibranch amplifiers and multiport nonlinear microwave systems in terms of power efficiency and signal distortion.

A De-Embedding Technique for On-Wafer Simultaneous Impedance and Power Flow Measurements

An absolute de-embedding technique for simultaneous impedance and power measurements suitable for on-wafer load-pull measurements of microwave transistors is proposed. This technique allows for the performance of a two-port power calibration of a vector network analyzer directly from the embedded reflection coefficient measurements. This method requires two sets of calibration standards, - one coaxial and one coplanar. Each set is comprised of three loads. An absolute power calibration performed at the coaxial reference planes using a reference power meter is also required for power measurement purposes at the coplanar reference planes of the microwave probes.

Dynamic distortion characterization of multiport RF PAs using MTA-based multiport measurement setup

This paper presents a dynamic AM-AM and AM-PM characterization of multiport RF power amplifiers. These measurements have been enabled by the multiport MTA-based measurement setup proposed in this paper. The setup provides simple, accurate, and time saving mechanism for these kinds of dynamic distortion characterizations since it is able to perform the measurements of multiport PAs in a single measurement shot. Finally, the measurements performed using the developed measurement setup on multiport balanced amplifier are presented.

An automated multiport measurement system for linear and non-linear characterization of N-port microwave devices

A measurement system based on microwave transition analyzer (MTA) as a receiver is proposed for time domain and frequency domain characterization of linear and non-linear N-port microwave devices. The proposed measurement system is able to perform full S-parameters characterization for N-port devices with only one measurement connection step. The system is also sensitive to the input power variation without the need of recalibration at each input power level.

A PROPOSED PROTOCOL TO ENHANCE THE PERFORMANCE OF WIRELESS SENSOR NETWORKS BASED ON THE REDUCTION OF POWER CONSUMPTION

This paper represents the analysis and study of selecting the highest power node in the wireless sensor networks as a cluster head. The study assumes that the sensors are fixed and uniformly distributed, and the position of the sink and the dimensions of the sensor are known. The paper introduces a proposed protocol to prolong the time interval before the death of the first node (stability period), which is critical for many applications. The aim of this paper is also to improve the performance of the network by increasing the overall throughput of the network. The proposed protocol selects the cluster head depending on the power level of the node which is the most important factor of the behavior of the nodes. The simulation is made by MATLAB, and the results are compared with two other protocols, LEACH and SEP. It is found that the selection of the highest power node as a cluster head increases the stability region and throughput of the network compared to other protocols.

Systematic Calibration of Two-Port Network Analyzer for Measurement and Engineering of Waveforms at Radio Frequency

This paper reports algorithm and technique for the accurate phase calibration in order to measure current and voltage waveforms at the terminals of two-port microwave devices. The calibration approach presented in this paper does not require any multi-harmonic coherent signal generator and golden standard, reported in earlier papers, thus allowing the system to be more reliable, generic and accurate. The results achieved using the reported calibration algorithm on a developed measurement setup shows good agreement with those obtained on a standard commercial scope. In the end, it has been shown that the developed algorithm and measurement setup can be adapted for carrying out waveform engineering which clearly identifles the application of this work in the characterization and measurement of microwave devices.

On-line waveform monitoring system for the design and characterization of MIMO RF PAs

A measurement system capable of relative waveform measurement and on-wafer power de-embedding is presented in this paper. A comprehensive description and calibration mechanism of the developed measurement system is reported. The calibration methodology has been implemented on a two-port Microwave Transition Analyzer (MTA) but is readily applicable to multiport receiver system. The calibration strategy is based on reflection measurement using open-short-load (OSL) calibration standards at each port of the measurement system. The proposed calibration algorithm is fast, simple and accurate for power de-embedding and waveform monitoring. This kind of on-wafer power de-embedding and waveform monitoring is helpful in the design of switching mode power amplifiers (PAs). Finally, the relative waveform measurement of a 3W GaAs FET demonstrates that the developed system is capable of accurately monitoring the input and output ports of multiport microwave devices.