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Design and Characterization of Integrated Varactors for RF Applications by Inigo Gutierrez download in pdf, ePub, iPad

Different architectures have also been described and multiple experimental results are given to characterize the different options. Description Varactors are passive semiconductor devices used in electroniccircuits, as a voltage-controlled way of storing energy in order toboost the amount of electric charge produced. In this case, these energies are defined by maximas. As the capacitance is variable, the resonant frequency fR is a function of the supply voltage.

The energy lost per cycle Edis will take different expressions depending on the simplified model of the varactor used, as shown below. Non-linear elements mainly include diodes and varactors.

It initially describes the physical phenomena that take place in the different types of variable capacitor structures currently available in standard integrated circuit fabrication processes. The aim is to achieve a wide capacitance variation range when working with a wide range of voltages. Other parameters of importance include the self-resonant frequency, maximum capacitance and the effective silicon area. The imaginary part of the reflection parameter represents the energy stored in the passive element, whereas the real part is the dissipated energy. Obviously, the fR must be as high as possible to avoid the incorrect functioning of the varactor.

The energy lost per cycle

On a passive network, the conservation of energy implies that the reflected and transmitted power on one of the ports must be less than or equal to the incident power. In other words, all the elements of the matrix must have a value that is equal to or less than the unit. For a better understanding, schematic cross sections of a typical wafer illustrating the electric and magnetic field distributions have been included.

Nonlinear elements mainly include