In wireless communication systems, the millimeter-wave frequency band has been gaining more interests recently, mainly due to its wide bandwidth and ability to support high data-rate. However, challenges come with the advantages. To transmit and receive complexed data, the quadrature amplitude modulation (QAM) scheme paired with orthogonal frequency-division multiplexing (OFDM) is used most commonly. In transmitter designs of such modulation schemes and frequency access schemes, two important requirements are high linearity and high efficiency. The building blocks of transmitters include power amplifiers (PA) and mixers. Nevertheless, traditional design techniques exhibit trade-offs between linearity and efficiency for PAs, and between conversion gain and linearity for mixers.
The nonlinear varactor-based parametric amplification theory can be applied to PA designs to improve both linearity and efficiency. Parametric amplification requires a pump waveform whose frequency is twice the operation frequency of the output waveform of the PA. The theory of parametric amplification is also applied to construct non-linear transmission lines, which is applied to mixer designs to improve both conversion gain and linearity.
The proposed PAs and mixers are designed and compared with conventional designs. For the PA, both power-added efficiency (PAE) and linearity are improved. For the mixer, both conversion gain and linearity are improved, and noise figure is lowered.
Previously, the theory of parametric amplification has been applied only to lower-frequency circuits, mainly due to the difficulty to generate a required pump signal, whose frequency needs to be twice of the signal frequency, at higher frequency ranges, such as the millimeter-wave (mm-Wave) frequency bands. This work demonstrates the feasibility of applying parametric amplification to circuits at mm-Wave frequency. In the PA design of this work, the pump is extracted from the second harmonic tone of the PA itself. As a result, the design complexity is simplified, the circuit area and DC power consumption are saved.
Dr. Gui Ping
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This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Huang, Sherry, "Parametric Amplification Study and Applications in Millimeter-Wave Transmitters" (2019). Electrical Engineering Theses and Dissertations. 26.
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