A. M. Pelaez-Perez

Large-Signal Oscillator Design Procedure Utilizing Analytical

New analytical behavioral model formulations based on the polyharmonic distortion (PHD) model have been successfully used to describe the nonlinear behavior of transistors and circuits. In this paper, the PHD model and its associated analytical X -parameters formulation will be utilized to provide an analytical design procedure for use in nonlinear microwave circuit design. For RF oscillator design, the negative-resistance method based on the analytical manipulation of scattering parameters is very popular due to its high rate of success in oscillation frequency prediction. However, it cannot be used to accurately predict the oscillator performance because it is based on linear parameters. To overcome this limitation, new analytical expressions based on large-signal X-parameters have been developed for use in transistor-based oscillator circuit design. The robustness of this new approach has been validated by designing and manufacturing a 5-GHz microwave oscillator.

X

Nowadays, millimeter-wave systems are being a key factor to develop wide band applications. In this paper, a directional coupler in millimeter-wave band using dielectric overlay is presented. This leads us to technology aspects, in directional coupler design, are key points to achieve the proper response of the circuit. The coupler proposed in this paper covers the 15{45GHz band and its response has 15-dB coupling-level, 1-dB coupling-ripple and a re∞ection coe-cient better than 10dB.

-Parameters Closed-Form Expressions

Recently, X -parameters have been introduced to model active device nonlinear behavior. In addition to providing a measurement-based tool to numerically predict nonlinear device behavior in computer-aided design, they can also provide the designer of nonlinear circuits an analytical design tool. Exploiting this design tool aspect, this work presents an application that combines the nonlinear vector network analyzer PNA-X and a passive tuner to extract a transistor load-independent X -parameter model, focused around targeted circuit impedances for optimal performance. Furthermore, an experimental search algorithm, based on X-parameters analytical computations and developed by Peláez-Pérez , has been used and experimentally validated in this paper, aimed to speed up the characterization and design process, minimizing the number of load-pull measurements necessary to provide an accurate transistor X-parameter model for use in analytical and/or numerical circuit design.

ULTRA-BROADBAND DIRECTIONAL COUPLERS USING MICROSTRIP WITH DIELECTRIC OVERLAY IN MILLIMETER-WAVE BAND

Recently, X-parameters have been introduced to model device non-linear behavior. In addition to providing a measurement-based tool to numerically predict non-linear device behavior in CAD, they can also provide the designer of nonlinear circuits an analytical design tool. Exploiting this design tool aspect, this work presents an application that combines the Nonlinear Vector Network Analyzer PNA-X and a passive tuner to extract a load-independent X-parameter model, focused around an optimized circuit target impedance. Furthermore, an experimental search algorithm based on X-parameters analytical computations, developed by the authors [1], has been used and experimentally validated in this paper, which purpose is to speed up the characterization/design process, minimizing the number of load-pull measurements necessary to provide an accurate X-parameter model for use in analytical/numerical circuit design.

Application of an NVNA-Based System and Load-Independent X-Parameters in Analytical Circuit Design Assisted by an Experimental Search Algorithm

To meet state-of-the-art specs in nonlinear circuit design for high frequency transceivers, we need computational efficient and reliable active device nonlinear models. Frequency-domain behavioral formulations, like X-parameters, have proven successful in this context. In this paper these formulations are exploited, through simplifications and transformations to the admittance/impedance domains, to algebraically guide the complex nonlinear design flow, in particular, in oscillator design. In addition, analytically the transistor behavioral model bandwidth can be extended, through the enhanced frequency scalability provided by the admittance domain. Simulations and measurements, HEMT and HBT devices will be used to validate the described approaches.