PhD candidate under CRest project at UM

Dr Narendra from University Malaya he is looking for 2 PhD (to be admitted in UM immediately); one for Motorola and Keysight projects, see the detail of the projects. This projects are funded by CREST.

Best Regards,
Prof Dr Mohamad Kamal A Rahim
Deputy Dean Research and Innovation
Universiti Teknologi Malaysia
81310 UTM JB Johor
Tel: 0137484664

Project 1
Executive Summary of Research Proposal
An 8 – 20 GHz microwave oscillator stabilized by a YIG crystal resonator is to be developed for electronic test instruments. YIG crystal is multi-octave tunable resonator, an un-doped YIG crystal lowest resonant frequency around 3.8GHz and theoretically no limit for maximum resonant frequency. Many microwave oscillators beyond 10 GHz employ FET as active device [1] due to FETs inherent high fT. A common base or common gate topology incorporating inductance at the base or gate, is employed either with BJT or FET to generate negative resistance over a broad bandwidth, as described in [2], [3] and [4]. Bipolar transistors are favored for oscillator design due to their low 1/f noise which translates to low phase noise [5].
New generation BJTs and HBTs when operating at low current (for good phase noise, IC should be about 10% of maximum current limit) have reduced fT; couples with an already low VCE resulting in low power, thus making it is difficult to operate wideband i.e. 8 20GHz. Most transistor models are valid up to < 10GHz. For a design to have high confidence of success, the model used in simulation must be valid within the frequency range of interest, even better, beyond. Thus, the model is to be incorporated in a design and simulate a condition that will yield negative resistance on the emitter port within the frequency range of interest. Then we translate the simulated design into the actual circuit for measurement and hence validating the model as well as the simulation.
In this collaborative research and development effort, the employment of wideband matching theory (gain-bandwidth limitation theory) with device technologies and applied EM knowledge will help us to synthesize broadband matching networks with selection of the appropriate broadband topology. The broadband matching network needs to fulfill bandwidth operation of 8 – 20 GHz microwave oscillator stabilized by a YIG crystal resonator is to be developed for electronic test instruments.
Success in this project will propel our local universities to the forefront of non-linear RF device characterization and modeling technology. With University Malaya setting up a cutting edge RF/ Microwave research lab, this project is an opportunity for the university’s electrical engineering department to move towards the forefront of the field of RF/ Microwave and applied electromagnetics internationally. In addition, as industry partners, Agilent (soon to be Keysight) can benefit from this project by reducing its design and engineering lead time as well as contribute towards the nurturing of local talents as well as boosting foreign investments in local high-tech companies.
BIBLIOGRAPHY \l 1033 [1] A. A. Sweet and R. Parrot, “A Novel Miniature YIG Tuned Oscillator Achieves Octave Tuning Bandwidth with Ultra Low Phase Noise in X and Ku Bands,” in Microwave Symposium Digest, 2006. IEEE MTT-S International , San Francisco, CA , 11-16 June 2006 .
[2] A. P. S. Khanna and J. Buenrostro, “2-22 GHz low phase noise silicon bipolar YIG tuned oscillator using composite feedback,” in Microwave Symposium Digest, 1992., IEEE MTT-S International , Albuquerque, NM, 1-5 June 1992.
[3] A. E. Muhammad Afifi, “YIG-tuned Oscillator Design on Printed Circuit Board using Surface Mount Technology,” in RF and Microwave Conference, 2006. RFM 2006. International , Putra Jaya, 12-14 Sept. 2006.
[4] R. J. Trew, “Octave-band GaAs f.e.t. y.i.g.-tuned oscillators,” Electronics Letters, vol. 13, no. 21, pp. 629-630, 13 October 1977.
[5] C. C. Leung, C. P. Snapp and V. Grande, “A 0.5 µm Silicon Bipolar Transistor for Low Phase Noise Oscillator Applications Up to 20 GHz,” in 1985, St. Louis, MO, 4-6 June.
Research background including problem statement and research methodology.

New generations of microwave Si bipolar transistors have high fT, as high as > 20GHz and in the case of SiGe HBT, the fT is as high as > 40GHz.This is achieved at a cost of reduced physical transistor structure and hence very much low operating VCE resulting in a narrow operating bandwidth for YTO. Secondly bare die transistors with the advantage of low parasitic elements are becoming rare nowadays due to low market demand couples with more complex process and higher cost as opposed to packaged versions. The smallest package available is SOT343F; while this packaged BJTs or HBTs can possibly work up to Ka band, they may not be able to, or poses great challenges in order to operate broadband YTO i.e. 8 – 20GHz. Due to gain-bandwidth theory limitation of the matching network to achieve lower quality loaded network, it is almost difficult to achieve negative resistance over the bandwidth of interest with present technique.
Objective(s) of the Research
This study embarks on the following objectives:
1) To characterize and perform device modeling of the selected device technology.
2) To investigate the wideband matching theory as part of broadbanding the oscillator design with YIG crystal resonator.
3) To design and fabricate wideband 8-20 GHz YIG-tuned oscillator design with silicon bipolar device technology.

 

 

 

Project 2

 

Motorola Project

Executive Summary of Research Proposal

The aim of this project is to study the utilization of X-parameters in the design of high power RF

transmitters in applications such as broadband LTE devices and two-way radios. The nonlinearity of

high power PAs and transmitters and the need to cascade these nonlinear devices limit the design

and engineering of PAs and transmitters to on board hardware tuning. Such an approach results in

costly engineering lead time and additional board runs. Utilization of state of the art X-parameters

opens up the possibility of applying reliable simulation results towards the design of nonlinear

electronic devices. [1-3]. The X-parameter behavioral model is extracted from a PA device via a

nonlinear network analyzer (NVNA) in combination with load-pull tuners [2,4]. The resulting X-

parameter model can be implemented in a RF circuit simulator such as Agilent ADS [5]. Additionally,

each nonlinear X-parameter model can be cascaded for the optimization of inter-stage matching in

the transmitter. This is a key objective for this research and development project.

The challenge for this project lies in correlating large-signal nonlinear simulations with measured

real-world results and applying the results to the engineering, design and optimization of two-way

radio performance. 3D Simulations will be used extensively to correlate the nonlinear X-parameter

models of RF devices to its real world performance and behavior. Once we have established the

correlation between X-parameter simulations and real-world transmitter performance, our next step

is to apply our findings towards the design of advanced broadband LTE power amplifiers for radio

communication applications. Since the demand for advanced LTE is increasing for data

communications, the proposed research effort drives towards the trend of wireless communications

technology, particularly for radio communication.

In this collaborative research and development effort, the employment of X-parameters in

combination with device technologies and applied EM knowledge will help us to synthesize

broadband matching networks with selection of the appropriate broadband topology (in this case:

switched mode class E) [7-9]. The broadband switched-mode class E with X-parameters approach

integrated with high level system on-chip (SOC) applied towards low cost device technology (e.g.

HBT or SiGe) will potentially achieve optimum DC-RF energy conversion (more than 45% efficiency)

over the prescribed bandwidth of 1.7-2.6 GHz [10,11].

An important part of this collaborative effort involves knowledge sharing of our findings. The end

goal of research is to disseminate knowledge for the collective advancement of science and

technology, therefore Motorola Solutions, Agilent Technologies and Universiti Malaya has also

committed to organizing seminars, road-shows/workshops on X-parameters for at least 5 universities

(including Universiti Malaya) in Peninsular Malaysia. The purpose of these seminars is to share

knowledge and findings on our research into X-parameters with these local universities in hopes of

generating further interest in RF and applied electromagnetics. Additionally, the NVNA will be

utilized as a shared resource (hosted by Universiti Malaya) for local universities interested in

pursuing X-parameter research in the future.

Success in this project will propel our local universities to the forefront of non-linear RF device

characterization and modeling technology. With Universiti Malaya setting up a cutting edge RF

research lab, this project is an opportunity for the university’s electrical engineering department to

move towards the forefront of the field of RF and applied electromagnetics internationally. In

addition, as industry partners, Motorola Solutions and Agilent (soon to be Keysight) can benefit from

this project by reducing its design and engineering lead time as well as contribute towards the

nurturing of local talents as well as boosting foreign investments in local high-tech companies.

References:

[1] David Vye, “Fundamentally Changing Nonlinear Microwave Design”, Microwave Journal Cover

Feature article, March 2010.

[2] G. Simpson et. al., “Load Pull + NVNA = Enhanced X Parameters for PA Designs with High

Mismatch and Technology-Independent Large Signal Device Models”, Maury Microwave Application

Note, March 2009.

[3] Jan Verspecht, David E. Root, “Polyharmonic Distortion Modeling”, IEEE Microwave Magazine,

June 2006.

[4] Agilent NVNA product brochure, http://cp.literature.agilent.com/litweb/pdf/5989-8575EN.pdf

[5] Agilent ADS http://www.home.agilent.com/en/pc-1297113/advanced-design-system-ads

6] T. Sowlati, C. Andre, T. Salama, J. Sitch, G. Rabjohn and D. Smith, “Low voltage, high efficiency

GaAs class-E power amplifiers for wireless transmitters”, IEEE J. Solid-State Circuits, vol. 30, no. 10,

Oct. 1995, pp. 1074-1080.

[7] C. Yoo and Q. Huang, “A Common-Gate Switched 0.9-W Class-E Power Amplifier with 41% PAE in

0.25-μm CMOS,” IEEE J. Solid-State Circuits, vol. 36, no. 5, May. 2001, pp. 823-830.

[8] A.V. Grebennikov and H. Jaeger, “Class E with parallel circuit-A new challenge for high-efficiency

RF and microwave power amplifiers,” IEEE MTT-S Digest., 2002, pp. 1627-1630.

[9] K. Narendra, C. Paoloni, E. Limiti, J. M. Collantes, R. H. Jansen and B. S. Yarman, “Vectorially

Combined Distributed Power Amplifiers for Software-Defined Radio Applications,” IEEE Trans.

Microwave Theory Technique, vol. 60, no. 10, pp. 3189-3200, Oct. 2012.

[10] J. Cumana, A. Grebennikov, S. Guolin, K. Narendra and R. H. Jansen, “An extended Topology of

Parallel-Circuit Class E Power Amplifier to account for Larger Output Capacitances,” IEEE Trans.

Microwave Theory Technique, vol. 59, no. 12, pp. 3174-3183, Dec. 2011.

[11] K. Narendra, C. Prakash C, G. Andrei and A. Mediano, “High Efficiency Broadband Parallel-Circuit

Class E RF Power Amplifier with Reactance Compensation Technique,” IEEE Trans. Microwave Theory

Technique, vol. 56, no. 3, pp. 604-612, Mar. 2008.

Research background including problem statement and research methodology.

Nonlinearity in radio components such as PAs and transmitters are difficult to design and engineer.

This is because it is very difficult to obtain a behavioral model that describes the nonlinearities of

these components. One MSc student will be assigned full time work in collaboration with Motorola

Solutions for the development of polyharmonic distortion modeling resulted by of means of

behavioral models for nonlinear devices. The X-parameters are based on the poly-harmonic

distortion model and is a mathematically consistent extension of Sparameters to the nonlinear

behavior (consideration of large signal regime). A huge advantage of the X-parameters is in enabling

the cascading of nonlinear devices, streamlining the radio design process.

Additionally, the demand for broadband advanced LTE standard (integration with other standards

e.g. CDMA, WCMDA, etc) is increasing and motivates broadband power amplifiers development with

high output power, efficient, and other radio regulatory standards (refer to FCC standard). To cover

next gen. broadband LTE standard i.e. 1.7-2.6 GHz is real challenge and no work has been

demonstrated up to now for radio communication applications. Future direction is moving towards

broadband LTE for radio communications. However, many research organizations are actively

looking into this research. This work will engage a PhD student (as full time in University Malaya) and

closely collaborate with Motorola Solutions for the broadband advanced LTE development with new

concept design methodology. The new concept design methodology will be focused on broadband

switched-mode class E with X-parameters approach integration with high level system on-chop (SOC)

in low cost device technology (e.g. HBT or SiGe) to drive for optimum DC-RF energy conversion

(efficiency more than 45%) over the prescribed bandwidth 1.7-2.6 GHz.

Objective(s) of the Research

This study embarks on the following objectives:

1) To characterize nonlinear behavior in power amplifier devices using X-parameters

and verify the validity of the X-parameter behavioral model.

2) To investigate the use of X-parameters to simulate realistic transmitter device

operation with the goal of streamlining radio design.

3) To design a broadband advanced LTE power amplifier (PA) employing X-

parameters approach for state-of-art engineering scientific that offers

frequency flexibility, ease of implementation, size reduction, and low power

consumption

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