YuWen Chang

4.9-GHz low-phase-noise transformer-based superharmonic-coupled GaInP/GaAs HBT QVCO

The low-phase-noise GaInP/GaAs heterojunction bipolar transistor (HBT) quadrature voltage controlled oscillator (QVCO) using transformer-based superharmonic coupling topology is demonstrated for the first time. The fully integrated QVCO at 4.87GHz has phase noise of -131dBc/Hz at 1-MHz offset frequency, output power of -4dBm and the figure of merit (FOM) -198dBc/Hz. The state-of-the-art phase noise FOM is attributed to the superior GaInP/GaAs HBT low-frequency device noise and the high quality transformer formed on the GaAs semi-insulating substrate.

Broadband GaInP/GaAs HBT Regenerative Frequency Divider with Active Loads

An integrated GalnP/GaAs heterojunction bipolar transistor (HBT) regenerative frequency divider (RFD) with active loads is demonstrated at 4 GHz -26 GHz. In this work, the RFDs with resistive loads and active loads are fabricated in the same chip for comparison. From the measured results, the active-loading type obviously has wider operating frequency and lower input sensitivity. The fmax/fmin ratio of 6.5 is higher than that of general RFDs. The core power consumption is 36.7 mW at the supply voltage of 5 V. The chip size is 1.0 times 1.0 mm2.

A High-Speed HBT Prescaler Based on the Divide-by-Two Topology

This paper demonstrates the Divide-by-4/5 prescalers with merged AND gates in 2 mum GalnP/GaAs heterojunction bipolar transistor (HBT) and 0.35 mum SiGe HBT technologies. By biasing the HBT near the peak transit-time frequency (fr), the maximum operating frequency of a D-type flip-flop (D-FF) can be promoted. At the supply voltage of 5 V, the GalnP/GaAs prescaler operates from 30 MHz to 5.2 GHz, and the SiGe prescaler has the higher-speed performance of 1 GHz ~ 8 GHz at the cost of power consumption.

4-GHz Low-Phase-Noise Transformer-Based Top-Series GaInP/GaAs HBT QVCO

The fully integrated GaInP/GaAs heterojunction bipolar transistor (HBT) transformer-based top-series quadrature voltage controlled oscillator (QVCO) is demonstrated at 4 GHz. The transformers on the semi-insulating GaAs substrate possess good electrical properties at high frequencies. The quadrature VCO at 4.1 GHz has phase noise of -120 dBc/Hz at 1MHz offset frequency, output power of 2 dBm and the figure of merit (FOM) -178 dBc/Hz

Low-phase-noise SiGe HBT VCOs using trifilar-transformer feedback

The SiGe heterojunction bipolar transistor (HBT) voltage controlled oscillators (VCOs) using trifilar-transformer feedback at emitters, bases and collectors are demonstrated. The integrated trifilar transformer can allow dual voltage swings across the collectors and emitters of a cross-coupled differential pair and separate the bias between bases and collectors to optimize the output power. The tank inductance is also improved by the mutual coupling of the trifilar transformer. Thus, 191 dBc/Hz FOM (figure of merit) is achieved and is comparable to that of the state-of-the-art VCO.

4-GHz Fully Monolithic SiGe HBT QVCO Using Superharmonic Coupling Topology

This paper demonstrates a 4-GHz monolithic SiGe heterojunction bipolar transistor (HBT) quadrature voltage controlled oscillator (QVCO) using superharmonic coupling topology. The quadrature VCO at 4.17 GHz has phase noise of -116 dBc/Hz at 1MHz offset frequency, output power of -6 dBm and the figure of merit (FOM) -179 dBc/Hz. The core current consumption is 3.2 mA at 3V supply voltage. The die size is about 1.4 mm times 1.2 mm

10 GHz GaInP/GaAs HBT Injection-Locked Frequency Divider

The first integrated GaInP/GaAs heterojunction bipolar transistor (HBT) injection-locked frequency divider (ILFD) with the stacked transformers is demonstrated at 9.60-10.38 GHz. The stacked transformers formed by only two metal layers provide the inductive coupling in the cross feedback and separate biasing for base and collector to allow for the larger voltage swing in the LC tank and increasing locking range. Under the supply voltage of 5 V and core power consumption of 20.5 mW, the locking range is up to 7.8% of the center operating frequency. Compared to other high frequency ILFDs employing a current source as signal injector, the design has a good performance in locking range. The chip size is 1.0 mm times 1.0 mm.

High performance GaInP/GaAs HBT radio frequency integrated circuits at 5 GHz

Several high performance GaInP/GaAs heterojunction bipolar transistor (HBT) radio frequency integrated circuits (RFICs) implemented by our research group are reviewed in this paper. These demonstrated RFICs include source inductively degenerated cascode low noise amplifiers with inter-stage matching, shunt-series shunt-shunt dual feedback wideband amplifiers, broad band Gilbert down-conversion micromixer, Gilbert down-conversion mixers with poly-phase filters for image rejection, Gilbert up-conversion mixers with output LC current mirror and quadrature VCOs. In addition, a method to extract the GaInP/GaAs HBT device structure is also developed.