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High-Speed SiGe HBT BiCMOS Circuits for Communication and Radar TransceiversKuo, Wei-Min 30 October 2006 (has links)
This dissertation explores high-speed silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) bipolar complementary metal oxide semiconductor (BiCMOS) circuits for next-generation ground- and space-based millimeter-wave (MMW >= 30 GHz) communication front-ends and X-band (8 to 12 GHz) radar (radio detection and ranging) modules. The requirements of next-generation transceivers, for both radar and communication applications, are low power, small size, light weight, low cost, high performance, and high reliability. For this purpose, the high-speed circuits that satisfy the demanding specifications of next-generation transceivers are implemented in SiGe HBT BiCMOS technology, and the device-circuit interactions of SiGe HBTs to transceiver building blocks for performance optimization and radiation tolerance are investigated.
For X-band radar module components, the dissertation covers:
(1) The design of an ultra-low-noise X-band SiGe HBT low-noise-amplifier (LNA).
(2) The design of low-loss shunt and series/shunt X-band Si CMOS single-pole double-throw (SPDT) switches.
(3) The design of a low-power X-band SiGe HBT LNA for near-space radar applications.
For MMW communication front-end circuits, the dissertation covers:
(4) The design of an inductorless SiGe HBT ring oscillator for MMW operation.
(5) The study of emitter scaling and device biasing on MMW SiGe HBT voltage-controlled oscillator (VCO) performance.
(6) The study of proton radiation on MMW SiGe HBT transceiver building blocks.
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Effect of the voltage dependency of the device-level gate-source capacitance in the linearity of a common-gate amplifierEduardo A. Garcia (5929682) 19 July 2022 (has links)
<p>Most work on amplifier linearity has focused on the transconductance (gm) linearity, but there is increasing evidence that the voltage-dependence of the gate-source capacitance (Cgs) plays an important role in the linearity of emerging devices. This work addresses the capacitance contribution by incorporating the nonlinearities attributed to the voltage dependency of Cgs of a general FET on a circuit-level Cg amplifier model.</p>
<p>An amplifier model including a voltage-dependent Cgs, and a voltage-dependent gm is studied using harmonic analysis and Volterra series. A closed form expression for the third-order intercept point (IP3) of the amplifier, which depends on the nonlinear coefficients of Cgs, is obtained. A simple design rule, and a formula for the reduction of the IP3 due to the voltage-dependent Cgs are also presented. </p>
<p>As application examples, the linearity of an amplifier based on a specific device is analyzed for two cases by extracting the nonlinear circuit parameters of the device. First for an analytic model of a bulk mosfet. Second for a one-dimensional, ballistic, coaxially gated Si nanowire. For low frequencies of design, the distortion introduced by gm is predominant, but for high frequencies it is obscured by the distortion coming from Cgs.</p>
<p>We conclude that taking into account the voltage-dependence of Cgs is crucial when predicting the linearity behavior of a Cg amplifier, either designed for high-frequency operation, or based on a device operating near the quantum capacitance limit. </p>
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Adaptive Suppression of Interfering Signals in Communication SystemsPelteku, Altin E. 21 April 2013 (has links)
The growth in the number of wireless devices and applications underscores the need for characterizing and mitigating interference induced problems such as distortion and blocking. A typical interference scenario involves the detection of a small amplitude signal of interest (SOI) in the presence of a large amplitude interfering signal; it is desirable to attenuate the interfering signal while preserving the integrity of SOI and an appropriate dynamic range. If the frequency of the interfering signal varies or is unknown, an adaptive notch function must be applied in order to maintain adequate attenuation. This work explores the performance space of a phase cancellation technique used in implementing the desired notch function for communication systems in the 1-3 GHz frequency range. A system level model constructed with MATLAB and related simulation results assist in building the theoretical foundation for setting performance bounds on the implemented solution and deriving hardware specifications for the RF notch subsystem devices. Simulations and measurements are presented for a Low Noise Amplifer (LNA), voltage variable attenuators, bandpass filters and phase shifters. Ultimately, full system tests provide a measure of merit for this work as well as invaluable lessons learned. The emphasis of this project is the on-wafer LNA measurements, dependence of IC system performance on mismatches and overall system performance tests. Where possible, predictions are plotted alongside measured data. The reasonable match between the two validates system and component models and more than compensates for the painstaking modeling efforts. Most importantly, using the signal to interferer ratio (SIR) as a figure of merit, experimental results demonstrate up to 58 dB of SIR improvement. This number represents a remarkable advancement in interference rejection at RF or microwave frequencies.
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Dvojitě vyvážený směšovač – laboratorní přípravek / Doble-balanced mixer - laboratory equipmentDušek, Libor January 2008 (has links)
The aim of this work was double-balanced mixer implementation, which will be used like laboratory equipment. This thesis deals with design of the double-balanced mixer from first theoretical principles to a practical design of a laboratory equipment. For the practical design the integrated mixer SA612 was used. Input signal to the mixer up to 500 MHz frequency can be used. For required operation external oscillator and fifth-order low pass filter were constructed. Oscillator was designed for fixed frequency 32 MHz. Fifth-order low pass filter was inserted between the mixer and the oscillator, because of filtering higher harmonics. The second aim of the work was measuring double-balanced mixer basic parameters, such as Compression Point (P-1dB) and Intercept Point (IP3). For the IP3 measurement, another one device was required. It consists of the power combiner for mixing two frequency close signals and third-order bandpass filter, which selects required frequency band. Finally, the laboratory equipment was fabricated and its real parameters were measured.
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