Department 3 is a work package in Newcom. There are 6 other work packages in Newcom like Department 3. Detailed information about Department 3 taken from Newcom official website is as follows:

Work packages > Department 3

Design, modeling and experimental characterisation of RF and microwave devices and subsystems

Introduction

Modern wireless communication systems are designed for multimedia applications, where person-to-person communication and/or access to information and services on public and private networks will be enhanced by higher data rates. The performance of the overall system is greatly influenced by the RF or microwave transmitter and receiver. A typical front-end coupled to an antenna is composed of passive and active blocks like low noise amplifiers (LNA), filters, oscillators, mixers, switches, power dividers/combiners, couplers, phase shifters, attenuators, driver amplifiers and power amplifers (PA). A high performance can be obtained by joint optimisation and design of all these components including the antenna. Higher data rates result in higher operation frequencies and this increase in the frequency makes the integration especially important. While the small size, low cost and power efficiency are key factors in handsets, low-noise, low cross-talk, high linearity and wide band performance are significant considerations in base-stations.

Research activities

Future RF systems will be increasingly large and complex. High integration technology can reduce the size and cost. A partial integration of building blocks has been customarily done in the form of microwave monolithic integrated circuits (MMIC). A full integration of the blocks or components can be done on the chip level (RF System on Chip - RF SoC) or on the package level (RF System-in-a Package - RF SiP). A successful integration requires the synergy of RF and analogue electronics breakthroughs in order to achieve dense integration, system miniaturisation and high performance of data transmissions up to very high bitrates. In the following, we outline the main research directions that have been merged into the unique work package of the Department.

Power amplifier linearization

Power amplifiers are essential parts of wireless systems. Modern amplifiers are built from solid state transistors like HBT's, HEMT's, MESFET's, HFET's or LDMOS's. Usually there is a trade-off between linearity and efficiency/size or cost. The nonlinear behaviour of these amplifiers have a large impact on the performance of many communication systems, especially for techniques where the communication signals has a large amplitude variation, such as OFDM and spread spectrum systems. The nonlinear distortions are created by transistors as well as by distributed effects due to the materials or metalic connections between devices. We plan to find system models of amplifiers, and try to combat the performance penalty by techniques like predistortion, nonlinear equalisation, coding, and baseband signal shaping. We propose to develop numerical tools based on Harmonic Balance method to predict the nonlinear performance of RF devices when they are subject to wideband signals, like the ones found in real communication environments. PA operation in the presence of non-constant envelope, wideband modulations is a challenge also from the standpoint of experimental characterisation procedures. We propose to develop load-pull based characterisation procedures both for power devices and for PA blocks in the presence of realistic modulated signals, with a view of optimising the PA design from the standpoint of linearity (e.g. ACPR) and efficiency (PAE).

Oscillator phase noise modeling and estimation

Phase noise in oscillators can be a severe limitation to system performance, especially in multicarrier systems where carriers may be closely spaced. We develop system models of oscillators, and study methods to reduce the effects of phase noise by phase estimation and pilot symbols. We will also try to get a better understanding on noise characterisation procedure for oscillator design, i.e. on how characterise baseband noise with a view to the noise conversion processes taking place in oscillators.

Micromechanical systems as filters in wireless applications

Cellular handsets have to be manufactured in hundreds of millions. Their filters require a technology which offers extremely low-cost, still with reasonably low-loss and high-selectivity. We are interested in assessing filters using micromachined electromechanical systems (MEMS). We also plan to develop and exploit powerful electromagnetic (EM) tools to design and optimise such structures at RF.

On the integration of microwave front-ends

Novel multilayered architectures, vertical interconnects and embedded components will be investigated for the effective integration of the subsystems and the minimisation of cross-talk and power losses. Achieving low loss structure also opens the way to designing high Q-structures. The thinner films - flex-foil used in new organic build-up technologies offers the ability to design and implement ultra-high density wiring required to package emerging and future high I/O chip technologies. In most cases, organic technology also has the potential for reducing system packaging cost. The wireless transfer and high bitrate requires efficient and wide band antennas integrated by SoC and/or SiP technique using organic and Si-based technology together with active and passive components. It is important to improve the radio coverage for WLAN and MIMO systems where passive and active reflect array antennas, so called retrodirective antennas can be used for this objective. The retrodirective antenna arrays can be designed (using for example differential Evolution Algorithm) to become an unequally spaced antenna arrays where the sidelobes can be controlled down to a very small level and the antenna system can be tailored for a particular radio environment. In dense electromagnetic environment with high data rates, filtering is an essential feature to pass only the desired frequency band and maintain these data rates. The synthesis of filters often requires extensive efforts in design. We would contribute to research new methods to facilitate the simple and rapid synthesis of filters with generalised transfer function. Base-stations demand low-loss and high-selective filters with small physical size. We are interested to research in the RF stage of a front-end receiver, containing an input filter and a LNA. The qualities of the RF stage can be considerably improved by incorporating cryogenic LNA with a high temperature superconducting (HTS) filter.

Integration

Collaborating in these areas will help develop the capabilities of all institutions. Forces will be joined for completion of complex projects where many man-year efforts are required. Tackling such projects may be too difficult for many institutions on their own. A collaborative effort will make such undertakings possible. Exchange of information between institutions will be a catalyst for further innovation.