Yinggang Li

A 25-GHz ultra-low phase noise InGaP/GaAs HBT VCO

A 25-GHz monolithic voltage controlled oscillator (VCO) has been designed and fabricated in a commercial InGaP/GaAs heterojunction bipolar transistor (HBT) process. This balanced VCO has a novel topology using a feedback /spl pi/-network and a common-emitter transistor configuration. Ultra-low phase noise is achieved: -106 dBc/Hz and -130 dBc/Hz at 100kHz and 1-MHz offset frequency, respectively. To the authors knowledge, this is the lowest phase noise achieved in a monolithic microwave integrated circuit (MMIC) VCO at such high frequency. The single-ended output power is -1 dBm. It can be tuned between 25.33GHz and 25.75GHz using the base-collector junction capacitor of the HBT as a varactor. The dc power consumption is 90mW for a 9-V supply. An excellent figure-of-merit of -195 dBc/Hz is obtained.

Transmission solutions and architectures for heterogeneous networks built as C-RANs

A novel end-to-end transport network solution is proposed to meet the operational and technical challenges of heterogeneous networks built as C-RANs with centralized base band processing and CPRI links. The flexibility of the proposed architecture to support distributed architectures and Ethernet links is also described and the results of a C-RAN proof of concept demonstration are discussed. Substantiated by the evolution of key optical technologies, including a novel WDM-PON based solution, we conclude that backhaul and metro network strategies need to flexibly support both centralized and distributed radio baseband solutions, as well as being multiservice capable. Additionally, as a complement to fiber, we propose use of the 70/80 GHz frequency band (E-band) to provide high performance microwave links for both centralized and distributed architectures.

Integration of a 140 GHz Packaged LTCC Grid Array Antenna With an InP Detector

Integration of a 140-GHz packaged low-temperature cofired ceramic (LTCC) antenna with a power detector is demonstrated under the concept of antenna-in-package. The detector is designed on an indium phosphide (InP) process. A grid array antenna in LTCC is designed to provide package for the detector. Coplanar ground-signal-ground (GSG) bond wires are used to connect the detector and the antenna. Parallel plate mode is observed in the InP substrate and absorbed by the LTCC substrate. The comparison between the measured responsivity of the power detector with and without the antenna indicates the acceptable insertion loss of the coplanar GSG bond wires transition. It shows a feasible solution for the D-band front-end integration and packaging.

A Novel FPGA-Based 2.5Gbps D-QPSK Modem for High Capacity Microwave Radios

A novel FPGA-based Differential QPSK modem (modulator and demodulator) is presented for data rates up to 2.5Gbps, in which no DAC or ADC is used. The targeted application is E-Band microwave Point-to-Point radio links in mobile backhaul for LTE and beyond.

A 14 Gbps On-/Off- Keying Modulator in GaAs HBT Technology

A proof of concept on-/off- keying (OOK) modulator is designed and implemented in a commercial heterojunction bipolar transistors IC process. The modulator circuit consists of an amplifier/latch structure, which is used as an OOK modulator for the first time. One of its advantages is that the topology may be implemented in both field effect transistor and bipolar technology. The measurement results correspond well with simulation and show that the modulator is capable of handling carrier frequencies up to 28 GHz, and data rates up to 14 Gbps. The isolation of the modulator in the off-state is better than 27 dB over the whole frequency range.

A Simple DBPSK Modem Based on High-Speed Logical Gates for a 70/80 GHz GbE Microwave Link.

A simple DBPSK modulator and demodulator based on high-speed logical gates is implemented. The modulator and demodulator is verified in a GbE microwave link for the 70/80 GHz band. Performance is evaluated back-to-back and in an outdoor hop over 1 km. We also show how the scheme may be extended to support the DQPSK format and thus double the capacity further.

A data-rate adaptable modem solution for millimeter-wave wireless fronthaul networks

For dense small cell deployment in centralized baseband architecture, wireless fronthaul is a cost efficient and flexible alternative to fiber-based fronthaul links. Due to the available wide bandwidth, millimeter-wave technology is the most promising choice to realize multi-gigabit wireless transmission of the common public radio interface (CPRI). In this paper, we present a novel differential encoding scheme for differential quadrature phase-shift keying (D-QPSK) modulation, which enables data-rate adaptable CPRI transmission without modification of a standard receiver. A multi-rate D-QPSK modulator/demodulator (modem) is implemented and tested for data rates up to 10 Gbps, limited by the bandwidth of the microwave components in use. This modem is verified to fulfill the CPRI specifications with respect to multi-rate, low latency and high system performance. Therefore, it is proposed for the implementation of wireless CPRI links at millimeter-wave bands.

A Compact 23 GHz Hartley VCO in 0.13μm CMOS Technology

A 23 GHz balanced Hartley VCO is designed and manufactured in 0.13 mum COMS technology. In this VCO design, a pair of coupled inductors are employed to make the whole circuit compact. Its size is only 0.17 mm2. Very low phase noise, -108 dBc/Hz at 1 MHz offset frequency, is measured and a wide tuning range of 13% is achieved. In addition, the VCO consumes only 5.7 mW dc power at 0.79 V supply voltage*.

A non-galvanic D-band MMIC-to-waveguide transition using eWLB packaging technology

This paper presents a novel D-band interconnect implemented in a low-cost embedded Wafer Level Ball Grid Array (eWLB) commercial process. The non-galvanic transition is realized through a slot antenna directly radiating to a standard air filled waveguide. The interconnect achieves low insertion loss and relatively wide bandwidth. The measured average insertion loss is 3 dB across a bandwidth of 22% covering the frequency range 110138 GHz. The measured average return loss is −10 dB across the same frequency range. Adopting the low-cost eWLB process and standard waveguides makes the transition an attractive solution for interconnects beyond 100 GHz. This solution enables mm-wave system on chip (SoC) to be manufactured and assembled in high volumes cost effectively. To the authors knowledge, this is first attempt to fabricate a packaging solution beyond 100 GHz using eWLB technology.

An active mixer topology for high linearity and high frequency applications

A new mixer topology is proposed which combines in parallel two single-balanced mixers, one Gilbert mixer and the other a so-called transconductance mixer. Such a mixer is supposed to improve linearity performance without degradation in noise figure and conversion gain. Based on the proposed topology, an active mixer operating at 23 GHz has been designed and fabricated in InGaP/GaAs technology. Under a power consumption of 52.6 mW, the measured IIP3 is +12 dBm, with 4 dB conversion gain and 11.5 dB double sideband noise figure.