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A Low Cost, Plastic Packaged, 0.5W, 6-18GHz Amplifier MMIC
|Stuart Glynn and Liam Devlin|
This article describes the design, fabrication and evaluation of a low cost 6 to 18GHz amplifier MMIC. It was designed to occupy a small die area on a high volume, optically defined process and to be packaged in a low cost standard QFN plastic package. The resulting part provides >10dB of gain across the 6 to 18GHz band and has an output P-1dB of +27dBm. The work was undertaken by the Plextek RF Integration design team, which specialises in the design of GaAs, SiGe and GaN MMICs and provides expert witness advice.
|A Low Cost, Plastic Packaged, 0.5W, 6-18GHz Amplifier MMIC|
A New Approach to Frequency Synthesis
|Speedwell Designs, Inc|
A new approach to frequency synthesis permits the achievement of excellent spectral purity, high agility, very fine resolution, low power consumption and low cost. The principle of the proposed Phase Digital Synthesizer (PDS) is that the control signal of the PLL is formed by a multi frequency-phase comparator with phase splitting of the reference and VCO signals into a large group of signals which are compared in the partial detectors. The outputs of these partial detectors are then summed to develop the VCO control voltage. The main advantage of the method is that there is no division ratio in the loop and thus there is no multiplication of noise and spurs normalized to the phase comparator. The synthesizer of PDS type can be used instead of complicated multi-loop systems which are too expensive, bulky and with high power consumption.
|A New Approach to Frequency Synthesis|
Advanced Materials for Ubiquitous Leading-edge Electromagnetic Technologies (AMULET) - what metamaterials can do for you
|Cobham Technical Services|
Metamaterials have been the subject of much academic research for the last decade. These artificially made materials show properties that are not found (or difficult to find) in natural materials, such as dielectric constants with negative or extremely large values. The use of the special properties of metamaterials is often constrained by narrowband, lossy or unstable behaviour which ultimately is related to electromagnetism fundamental limits. The work developed under AMULET has focussed on using metamaterial concepts applied for practical devices with realistic specifications and performance goals, avoiding the usual metamaterial limitations. A number of prototypes have been developed and tested during this programme, including a non reciprocal CP Ferrite GPS antenna fully compliant with aviation standard, low-loss large DK artificial materials applied to miniature patch antennas, 20/30GHz orthogonal CP screen polariser for Ka band Satcom, Negative Immitance Converter (NIC) for broadband matching of electrically small VHF antennas and high performance radiating surface flat plates for Satcom applications.
|Advanced Materials for Ubiquitous Leading-edge Electromagnetic Technologies (AMULET) - what metamaterials can do for you|
Airborne to Spaceborne - Qualifying a Passive Radiometer for Spaceflight
A microwave radiometer is a noise measuring instrument comprised of two RF assemblies, which consists of bespoke millimetre wave equipment at the front-end of the instrument and IF assemblies, of generally off-the-shelf components, at the back-end of the instrument, before conversion of the RF input to a DC output for further processing. In terms of a UK project, like the Met Office instrument being upgraded under the European Space Agency (ESA) Cloud and Precipitation Airborne Radiometer (CPAR) project, the instrument front-ends, being above 43GHz, would be covered by UK export controls, but the IF assemblies, although much lower in frequency, are, in some areas, subject to US EAR99 and potentially ITAR restrictions. The European Space Agency and EUMETSAT are planning to build a series of radiometers for flight on the Second Generation Operational Polar Orbiter Mission (METOP2G) with development likely to commence in 2013. For RF spaceborne applications virtually all US RF components are covered by ITAR. So for European based Space projects European sources of radiation-hardened standard components (mixers, multipliers, oscillators, amplifiers etc) are required, thus avoiding the complexities of ITAR for each new future project. In this paper we present a survey of the available radiation-hardened microwave technologies in Europe and where technologies need to be developed for spaceborne radiometry outside of ITAR restrictions. This represents an opportunity for European based MMIC foundries to provide RF radiation-hardened components, using industry standard build-to-print designs, into the spaceborne radiometer marketplace.
|Airborne to Spaceborne - Qualifying a Passive Radiometer for Spaceflight|
Broadband and Low Profile Antenna for UHF Band
|Loughborough University / Antrum Ltd|
The requirement of wideband and compact devices is ever increasing in most communication systems. In addition, recent increases in the transmission and reception of information have created a need for broadband and low profile antennas. This necessity is particularly challenging in designing Radio Frequency (RF) products that demand these features at low RF bands. There are numerous situations in which environmental considerations and application require the antenna to also be low-profile. This paper discus a study performed in a novel, broadband, low cost and low profile antenna in the UHF band. This has been achieved through numerical modelling, theoretical investigation and physical measurements. The dual side Printed dipole antenna (PDA) is used as a main radiating element. Also the use of the microstripe tapered balun and the parasitic elements increase the operation band of the antenna. The surface current distribution for the maximum and zero values is extracted and examined at various frequencies to prove the broadband balancing phenomena. The PDA is optimised to work within 470MHz - 850MHz band. The achieved bandwidth is 53%. The simulated antenna efficiency varies from 88% to 97.7%. The PDA directivity and gain values are as high as 4.3dBi and 4.1dBi respectively. Measured and simulated results are in good agreement.
|Broadband and Low Profile Antenna for UHF Band|
Challenges of Making Precise Power Measurements at RF, Microwave and Millimeter-wave Frequencies
|Rohde & Schwarz|
Power meters have a very high degree of accuracy when compared with other instruments for measuring high-frequency quantities. This paper discusses the major sources of error and how to select the appropriate measuring instruments for demanding power measurements. It also demonstrates the tremendous strides that have been made in the past decade, leading to improved usability, increased measurement speeds and, in particular, greater accuracy of power sensors under real-world conditions.
|Challenges of Making Precise Power Measurements at RF, Microwave and Millimeter-wave Frequencies|
Design, Fabrication and Test Results of a 15W 10GHz Hybrid Power Amplifier Using TGF2023-05 GaN Discrete HEMT
The paper will describe a design method that has been used successfully in-house for a number of amplifiers using discrete GaN transistors. The importance of using electromagnetic simulation for input and output networks will be discussed, together with accurate models for bondwires. A design example will be presented for a 15W X-Band power amplifier using a commercially available multi-cell GaN HEMT device. Simulated and measured small-signal, power and efficiency performance will be compared, together with results in a communications application.
|Design, Fabrication and Test Results of a 15W 10GHz Hybrid Power Amplifier Using TGF2023-05 GaN Discrete HEMT|
Forty Years of Technology in Microwave Receivers at The GEC Hirst Research Centre - A Brief History 1940’s to 1980’s
The GEC Research Laboratories, later GEC Hirst Research Centre, was among the world leaders in progressing microwave receiver technology from the 1940’s to the 1980’s. A brief review is provided of some of its technology advances for application in microwave heterodyne receiver developments over that period, through the phases of the waveguide/coaxial point-contact diode, then the planar device/circuit for the hybrid MIC (Microwave Integrated Circuit) using microstrip as the transmission media, and finally the early MMIC (Monolithic Microwave Integrated Circuit)
|Forty Years of Technology in Microwave Receivers at The GEC Hirst Research Centre - A Brief History 1940’s to 1980’s|
Frequency Discriminators for Broadband Applications
Frequency discriminators are widely used in Electronic Warfare Systems for the instantaneous frequency measurement of intercepted signals, allowing rapid identification of threat emitters. This paper reviews microwave discriminator architectures based on multiple delay line, phase measurement and parallel digital processing, designed for operation over decade bandwidths. An alternative reflection mode discriminator architecture is introduced which exhibits the advantages of simplicity, compact realization and can be designed over broad bandwidths. The principle of operation, circuit design techniques and frequency measurement performance are described and examples are given of mature designs which have been successfully manufactured in production quantities.
|Frequency Discriminators for Broadband Applications|
From Active Metamaterials to Transformation Electromagnetics: AMULET from the academic's perspective
|Khalid Rajab & Yang Hao|
|Queen Mary University of London|
Metamaterials have captured the imagination of scientists and engineers, as well as the general public, with the promise of the practical realisation of devices that are seemingly out of science fiction. The ability to control the properties of a material by altering its geometrical structure is an old idea, but due to the convergence of a number of factors, this has led to a recent paradigm shift in the approach to the solution of electromagnetic problems, as well as to device design. These approaches have led to realisations of invisibility and illusion cloaks, optical black holes, improved lenses, and a host of other devices. Transformation electromagnetics is a recently developed methodology that allows the construction of a range of electromagnetic structures. The basic idea is that a mathematical transformation of space can be represented by a change in the material properties. To create an invisibility cloak for example, the space around an object is transformed into a point, and so it appears infinitesimally small to any incoming electromagnetic waves. The drawback is that the resulting materials may have unnatural or hard to find properties (anisotropic, magnetic, or with ε,μ<1). As is the case with antennas, fundamental limitations will restrict their properties such that they are narrow-banded and lossy. We will demonstrate tools for realising many of these structures using commonly found materials (particularly isotropic dielectrics). We will also discuss our work into the next step in the evolution of metamaterials: active metamaterials.
|From Active Metamaterials to Transformation Electromagnetics: AMULET from the academic's perspective|
High Impedance Surface Electromagnetic Band Gap Metamaterials: Design approach and applications for antenna engineering
|National Physical Laboratory|
Important considerations for antenna designers of compact high data rate wireless communications systems are wideband performance and antenna size reduction. However, in many cases, for the size reduction, the main problem is the reduction of ground plane size, given the limited area available on the platforms. Such reduction means an increase in antenna backward radiation even for larger sizes, a normal conducting metal ground plane allows for surface wave propagation, which also contributes to backward radiation via edge diffraction. The mushroom-like high impedance surface Electromagnetic Band Gap (HIS-EBG) structures exhibit high surface impedances for both TE and TM polarisations and can suppress the surface wave propagation at certain frequency ranges. Furthermore, the surface wave band gap property of HIS-EBG helps to increase the antenna gain, minimise the back lobe, and reduce mutual coupling. Hence, they have played an important role in recent developments of new materials for application in wireless radio communications and antenna engineering. This paper presents a theoretical study, design approaches and the applications of mushroom-like High Impedance Surface Electromagnetic Band Gap (HIS-EBG) metamaterials in antenna engineering. The work focuses on techniques for developing HIS-EBG metamaterials that are wideband and compact in size using an electrically tunable approach. A tunable HIS-EBG structure is represented by a novel analytic equivalent transmission line circuit model for surface wave propagation. The analytical and numerical simulations and a parametric study on the effects of patch width, gap width, substrate thickness and substrate permittivity are presented.
|High Impedance Surface Electromagnetic Band Gap Metamaterials: Design approach and applications for antenna engineering|
Quantifying Frequency Coherence: A Variation on the Heterodyne Method of Allan Deviation Measurement
|Orban Microwave Products|
In our highly connected society, the ability to precisely synchronize many remote clocks and oscillators to primary (atomic) frequency references is indispensible for commercial, scientific, medical and everyday personal uses such as navigation and digital broadcasting. The quality of these services depends heavily on the precise tracking of the atomic reference by the phase-locked local oscillator (often in a low carrier to noise environment). In this paper, we review some of the theoretical background of phase locked oscillators and the definition of Allan deviation (ADEV) as well as why the usual phase error definition is inadequate. Some of the common existing measurement methods are reviewed as well as an outline of the approach used in our measurements. We then verify the method by providing the example of a precision Doppler measurement (like what one might see in a deep space radio science experiment) and how ADEV provides a way to quantify errors in the scientific results.
|Quantifying Frequency Coherence: A Variation on the Heterodyne Method of Allan Deviation Measurement|
Understanding the Effect of Uncorrelated Phase Noise on Multi-channel RF Vector Signal Analysers
|National Instruments UK|
While MIMO test set-ups historically used multiple vector signal analysers (VSAs) with a shared 10 MHz reference clock, the rise of modular RF instruments allows for a common local oscillator (LO) to be shared between each channel of a multi-channel VSA. In multi-channel VSA systems, a broad range of factors can introduce measured channel-to-channel phase variation including: uncorrelated LO phase noise, uncorrelated ADC sample clock phase noise, signal to noise ratio (SNR) and ADC quantisation noise. In this session, we will discuss and compare a selection of methods for multichannel synchronisation and discuss how to mitigate against these sources of channel-to-channel phase error by synthesising and sharing LOs across channels and downconverter chains.
|Understanding the Effect of Uncorrelated Phase Noise on Multi-channel RF Vector Signal Analysers|
Using EM Planar Simulators for Estimating the Q of Spiral Inductors
|Applied Wave Research Ltd|
Electromagnetic (EM) simulators have been widely used to model spiral inductors in silicon and gallium arsenide chips. The quality factor, commonly referred as Q is the most important figure of merit for such a device. However, estimating the Q can be quite a challenging task for an EM simulator since the calculation of resistive losses in the conductor is required. Planar EM simulators rely on impedance boundary condition (IBC), which suffers from inaccuracy at edges and corners of the conductors. Besides, for an accurate estimation, the mesh on the conductors must be very fine thus leading to a large computational problem. Three dimensional EM simulators suffer from similar problems since the interior part of the metal must be meshed very finely for an accurate calculation of the resistive losses. In this paper we present an innovative and fast method for an accurate Q calculation. First a planar EM simulator with normal mesh size is used; then a cross sectional solver (available at low cost) is used to estimate the losses in coupled transmission lines. The result of the second simulation is used to correct the estimation of the planar simulator. Comparisons with measurements have proven the accuracy of the proposed technique.
|Using EM Planar Simulators for Estimating the Q of Spiral Inductors|
Which Electromagnetic (EM) Simulation Method Should I Use?
Driven largely by ever high levels of circuit integration and complexity, the use of electromagnetic (EM) field solvers is becoming increasingly important to many RF/Microwave Designers and High Speed Digital Designers. Whilst commercial computer aided design (CAD) tools are widely used in the industry for analysing circuits using a circuit theory approach, the use of EM field solvers is less pervasive and for many, EM simulation is regarded as something of a ‘Dark art’. Several key EM simulation technologies have emerged over recent years, these include the Method of Moments (MoM), Finite Element (FEM) and Finite Difference Time Domain (FDTD) solutions. Although in principal these technologies could be used to solve the same problems there are often good practical reasons why one particular simulator is better suited to solving a particular problem. This paper will outline three of the key EM simulation technologies and attempt to highlight some important considerations when selecting a particular technology and compare/contrast the relative merits of each.
|Which Electromagnetic (EM) Simulation Method Should I Use?|
Contributions are invited with an emphasis on RF and microwave design, research, testing and associated subjects. An oral presentation will be made at the meeting and a written paper will be required for publication in the society digest, which is distributed to delegates at the meeting. Prospective speakers are requested to submit a title and a short abstract to the technical coordinator (see above) as soon as possible.