Armms RF and Microwave Society

Conferences

Next Conference:

Monday 13th November to Tuesday 14th November 2017 at Wyboston Lakes, Wyboston

The November 2017 is now fully booked, no additional places can be made available.

Young Engineer Sponsorship: The ARMMS RF & Microwave Society provides sponsorship for young engineers (28 or below) who have had papers accepted for presentation at each meeting. Sponsorship is £100 cash plus free attendance (including conference dinner and overnight accommodation). Potential candidates should identify themselves as eligible at time of submission and state their date of birth. This offer is limited to a maximum of 2 places per meeting.

Best Paper Award: The Steve Evans-Pughe prize is awarded to the best presenter at each meeting. The award is £200 for the best paper and £50 for the runner-up. The prize is sponsored by NI.

If you are interested in submitting a paper for presentation at this conference, please contact the technical coordinator (details below). Papers currently listed below are those already accepted. The deadline for submissions is September 19th. For all other enquiries please email enquiries@armms.org

VENUE

Wyboston Lakes
Great North Road
Wyboston
Bedfordshire
MK44 3AL

Tel0333 7007 667
Emailsales@wybostonlakes.co.uk
Webhttp://www.wybostonlakes.co.uk/

PROGRAMME CO-ORDINATOR

Chris Buck
Filtronic Broadband

Tel+44 191 308 2149
EmailChris.Buck@filtronic.com

PAPERS

'Mind the Gap' . . . Establishing Measurement Capability in the Terahertz Gap Region - from 0.1 THz to 1.1 THz

Nick Ridler
NPL

In recent years, there has been a significant increase in the availability of test and measurement equipment operating in the 0.1 THz to 1.1 THz region.  This region has traditionally been referred to as the “Terahertz Gap” because it corresponds to a gap, in the electromagnetic spectrum, between the use of electronics capabilities (operating at RF and microwave frequencies) and photonics capabilities (operating at optical frequencies).  The extension, into the terahertz gap region, of electronics capabilities based around vector network analysers has been mainly responsible for this increase in measurement capability.

The talk will review the current state-of-the-art of measurements made using vector network analysers operating in the 0.1 THz to 1.1 THz frequency range.  The talk will concentrate on the development of three types of measurement capability: (i) in rectangular metallic waveguides; (ii) for on-wafer planar circuits; (iii) for bulk material characterisation.  The talk will discuss progress to date with establishing this measurement capability and will also review the remaining challenges facing this measurement community.       


3D Printed Circuits for RF and Microwave Applications

Xiaobang Shang
Birmingham University

3-D printing is a promising technique to produce RF and microwave passive circuits. Compared with conventional machining techniques, 3-D printing enables manufacturing complex structures with great geometrical complexity and/or printing the devices into a standalone part without the need of further assembly. Another great advantage of 3-D printing is the significant weight reduction, when the device is printed from polymer and metal coated. 

This paper will present a range of 3-D printed passive circuits investigated at the University of Birmingham. These circuits cover a wide frequency range, from 0.5GHz to 100GHz, and consist of filters, OMT and Butler matrix. Most of the devices are based on lightweight polymers, which are capable of handling high temperature when ceramic filled resin is used.  3-D metal printing is also utilised to produce several designs including a W-band filter. All of the circuits are optimised for 3-D printing, so that enhanced microwave performance and/or considerable weight reduction can be achieved. This cluster of work demonstrates the great potential of using 3-D printing for microwave applications.


5G mmWave implementation options

Chris Clifron
Sony
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Antenna Beam Steering Without Phase Shifters - an 'Old' Technique Revisited

Eddie Ball and Alan Tennant
University of Sheffield

Antenna arrays have a perennial interest and relevance to RF wireless system designers, indeed the rise of 5G is showing their importance is only growing. Most implementations of linear arrays use phase shifters to feed the array and hence form the main-lobe beam. In the 1960s, a technique using RF switches and Fourier analysis was discovered to be a viable alternative to phase shifters - called the Time Modulated Array (TMA). Little modern research has been conducted in this area, despite its likely cost-effective implementation and technical relevance.

This paper presents a brief overview of the TMA, followed by our work into prediction and control of the RF harmonic levels in TMAs. The effect of RF ramping on the switching waveform is analysed first, followed by a novel way of reducing the carrier fundamental (due to the Fourier DC term) produced by TMAs. Finally, a novel RF transistor cascode fast switch is introduced, using 3 gain states, to pragmatically implement the reduction of the carrier fundamental. The transistor cascode in the TMA utilizes binary logic control interfaces, rather than analogue control interfaces, for hardware efficiency. Early simulation results are included.


Can Lower Q Resonators Produce Better Filters?

John Kitchen
SJTechnologie

With the exception of Superconducting Filters, no one uses microstrip filters in the expectation of getting leading edge filter performance. Microstrip filters are used for reasons of Cost, Convenience and Size. However, is it possible to deliberately reduce the Q-factor of the resonators used in order to achieve a better filter?

Whether a filter is “better” will depend upon your specific requirements. You may want a smaller filter, or a wider stop band, or rejection in the harmonic bands, or even rejection to a higher frequency without waveguide modes taking over.

This paper looks at options available to the filter designer to see if one can deliberately choose to use lower Q resonators to achieve improvements in performance.


High Efficiency Microwave Power Amplifiers for Portable Haemostasis Application

Abdul Moiz Ahmed Pirkani*, Shaun Preston**, Christopher I Duff*, Christopher Hancock**
*The University of Manchester, **Bangor University

Uncontrolled haemorrhage from major trauma is leading mechanisms of death on the battlefield. Studies have shown that this is the case in up to 80% of potentially survivable cases and that approximately 69% of these cases were either torso or junctional based and would be unsuitable for treatment with standard tourniquet methods.

Presented herein is a portable microwave applicator capable of delivering microwave energy at 5.8 GHz to effectively coagulate bleeding sites which cannot easily be controlled under conventional haemostatic modalities. Using similar methods as used in operating theatres for the closure of bleeding vessels during surgery the device can coagulate both blood and specific vessels. This could be used an interim process to facilitate emergency evacuation to a suitable facility or, depending on severity, it can act as a longer-term solution if other facilities are not readily available.

The device consists of a handheld applicator with a radiative tip shaped to allow the user to apply local tamponade to the site whilst delivering energy thus increasing the likelihood of haemostasis. Microwave power of sufficient level to achieve haemostasis is produced within the “power pack” by means of a high efficiency class F power amplifier capable of producing up to 15 W. High efficiency operation of the power amplifier limits the amount of dissipated heat and DC power consumption. Active cooling mechanisms permit effective heat transfer for continuous use of the microwave applicator whilst a removeable battery provides sufficient DC power for each coagulation process and can easily be replaced if further energy delivery is required.


High Gain, Multi-stage GaN Line-up for Ultra-compact Design

Chris Harris
Wolfspeed

GaN devices have revolutionized the capability of high power RF devices by enabling them to operate at high voltage. Higher voltage and the resulting higher power density, lowers the output capacitance of such devices providing a higher impedance with the advantage of easier matching and improved performance.  Until now GaN has primarily been used in the output stage of high power amplifiers where the technology advantages are most evident; unfortunately the implication for the circuit designer is that different stages of the PA design have required different voltage levels, sometimes with as many as 4 voltage levels present on a PCB!  Wolfspeed has now started the introduction of MMIC based drivers that provide very high gain while operating at the same voltage as the power stage of a design. The result is a compact design with over 50dB of small signal gain from 2 devices.   The benefits are significant, not least the dramatic space saving achieved from a combination of fewer devices and a single bias voltage.  This presentation will present results from an S-band radar example of the above concept, in this case the two products are a QFN based 2-stage MMIC used as a driver and a partially matched metal ceramic packaged HEMT transistor, CMPA2735015S and CGHV35150F respectively.  The application circuit has been used to demonstrate Wolfspeed GaN HEMT technology capabilities with respect to harmonic content and power added efficiency (PAE) in a design optimized for size weight and power (SWaP).  The key features of this circuit are:

 

  • 500MHz Instantaneous Bandwidth
  • 53 dB Small-Signal Gain
  • 48dB Associated Power Gain (up to 170W output power)
  • 45% Power Added Efficiency at 170W average power (3.1 to 3.6 GHz)
  • -45dBc worst case Harmonic content (H2 through H5) at up to peak Efficiency
  • Minimum Physical size: 0.9in x 2.2in (23mm x 56mm)

 

Details of the circuit will be discussed for further understanding of the topology.  Further examples from Wolfspeed’s portfolio of high gain driver MMICs will also be discussed.


High-resolution Thermoreflectance Imaging of Power Microwave Transistors

Peter Aean
Surrey University

The ever-increasing power density of semiconductors used in monolithic microwave integrated circuits (MMICs) and power amplifiers (PAs) mandates good thermal management and accurate temperature measurements are needed to study device reliability, assess temperature gradients, and to validate nonlinear electrothermal model performance.

Thermoreflectance based temperature measurements have been recently applied to high-power microwave semiconductors. The technique determines the temperature by measuring the change in reflectance from a surface due to changing in the index of refraction of the sample.  Since the measurement technique uses visible light, thermoreflectance imaging can achieve a spatial resolution of 290 nm and sub-nanosecond temporal resolution over a wide field of view.   This makes the method well suited to study the thermal dynamics within these transistors.

This presentation will review the capabilities of thermoreflectance measurement, explain the theory behind the thermoreflectance phenomenon, and demonstrate the usefulness of the method and the insights that can be gained by examining several recent measurements.


Microwaves, Metamaterials and Additive Manufacturing

Darren Cadman
Loughborough University

3D printing is a manufacturing platform that is moving from the research labs and into industrial applications and consumer markets. It falls under the wider term of Additive Manufacturing that encompasses various processes suitable for different end user requirements. This presentation will give an overview of some of those processes and their use and applicability to microwave applications. The presentation is against the backdrop of Loughborough University’s lead on the Engineering & Physical Science Research Council’s £5 million Grand Challenge project “Synthesising 3D metamaterials for RF, microwave and THz applications: SYMETA”. The project has universities at Exeter, Oxford, Queen Mary London and Sheffield as academic partners with the aims of exploring additive manufacturing processes to create novel high frequency substrates, passive circuitry and antennas all using metamaterial concepts. An overview of the project will be given with some of the early results emanating from the project.


Millimeter Wave Band Propagation Studies for 5G Networks

Sana Salous
Durham University

Several frequency bands in the range 24-86 GHz have been identified by WRC15 as possible frequencies for future 5G radio networks.  To evaluate the radio channel in these bands, Durham University performed propagation studies in the frequency bands 25-28 GHz, 51-57 GHz and 67-73 GHz using the state of the art multiband Durham channel sounder. Using two transmit and two receive channels in each band, dual polarised measurements of typical indoor and outdoor environments were analysed to estimate a number of channel parameters such as path loss, delay spread and cross polar discrimination.  Results of both directional and omni-directional measurements will be presented outlining contributions to the international telecommunication union recommendations. 


Millimetre Wave Point to Multipoint Enabled by a Novel W-band Traveling Wave Tube

Claudio Paoloni
Lancaster University

The Horizon 2020 TWEETHER projects aims to build a point to multipoint wireless system with high capacity at W-band (92 – 95 GHz) for backhaul of small cells and fixed access. The point to multipoint is an attractive solution for backhaul. It is much cheaper than the fibre and needs only half of the equipment of an equivalent point to point backhaul. The W-band was chosen due to the light licensing and the low cost for operators. The use for the first time of a novel high power traveling wave tube permits to cover wide angle sectors with range of about 1 km, providing about 10Gbps/km2 capacity density.

The paper will describe the network architecture and the components purposely designed and fabricated for the transmission hub and the network terminal equipment.


On Wafer and Package Test with an Industrial Solution for MMIC Components

Jean-Francois Provost
UMS

Test approaches have changed over the last years led by the high volume market, the complexity and the diversity of the functions (bare dies and packages) to be tested in a production environment.

Both Software and Hardware developments have been required.

Among these works, three examples are illustrated in this paper:

  • Development of pulsed power test bench: combination of new equipment generation and powerful test software. Our approach is based on parallelization of multi parameter measurements, capture simultaneously power sweep and pulsed current (very fast test time). These test benches are used for high power circuits designed on GaAs and GaN technologies
  • Development of E-band test benches for on wafer test (LNA, Multiplier, PA, IQ up and down converters)
  • Development of software tools for data analysis and decision making (setup validation, monitoring in real time...)

 

The advance test solution integrates different measurement types: DC, noise, [S] parameters up to 110GHz, power measurements and conversion gain up to 86GHz.

The benefits are a higher flexibility, an easy and fast data access, test time reduction and wide test offers at high frequency.


Review of Filter Bank Techniques - RF and Digital

John Lillington
Libra Design Associates Limited

Filter banks and tunable filters form  key elements of system and receiver design. Many will be familiar with the various types of analogue filter but, with the advent of ever higher ADC conversion rates, digital filters are displacing analogue in an increasing number of applications. Although digital filters can offer performance parameters not available to analogue designs, there is often a price to pay in terms of power and cost and, in some cases, this approach may not even be the best option.

This paper aims to look at the trade-offs between the two types as well as typical examples of techniques used, particularly the less familiar types of digital filter bank.


Schottky Diode Based Frequency Sources to 360 GHz

Jeff Powell, Colin Veigas, Hairui Lui and Byron Alderman
Teratech Components Ltd

Signal sources at 100s of GHz rely on technology which is not used in mass production and has traditionally been subject to significant variation in manufacturing accuracy and therefore performance.  Although the relatively recent emergence of MMIC amplifier circuit technologies has demonstrated circuits to a few 100 GHz, the highest power and frequency outputs use Schottky diode based circuits.  In this paper examples of European state-of-the-art frequency multipliers are reported (for example, 100mW Pout at 180GHz) which demonstrate how MMIC-type approaches are employed to improve the performance and ‘useability’ of planar Schottky diode technology beyond 300 GHz.


The Design of 1 KW GaN Solid State Power Amplifier at 2.45 GHz

Avtar Virdee
Microwave Technology Ltd

This paper presents the design, implementation and experimental results of a 1 KW GaN solid state power amplifier operating at 2.45 GHz. The solid state power amplifier employs twelve single stage high-efficiency GaN-HEMT power amplifiers that are operating in Class-F mode of operation. The twelve single stage high-efficiency GaN power amplifiers are combined using low loss power combiner circuits. The GaN device constituting the amplifier is a commercial off-the-shelf device that is designed for high voltage operation. The 1 KW GaN solid state power has been designed to operate with RF pulsed and continuous wave mode inputs.


The Design of a Dual-Band PA for mm-Wave 5G Applications

Liam Devlin and Stuart Glynn
Plextek RFI

Considerable time and money are currently being invested in developing millimeter-wave technology for 5G, and there is much debate and lobbying around the most suitable frequency bands for this application. Development work is currently underway in many candidate bands and it is looking increasingly unlikely that a single band will be designated on a worldwide basis for millimeter-wave 5G in the immediate future. This means that the availability of dual-band or multi-band millimeter-wave components will become increasingly attractive.

This paper will describe the design, layout, and performance of a dual-band power amplifier (PA) monolithic microwave integrated circuit (MMIC), capable of electronically switching its operating band between the 26GHz pioneer band identified by the EU's RSPG (24.25 to 27.5 GHz) and the 32GHz band (31.8 to 33.4 GHz). The design was implemented on a commercially available 0.15µm gate length pHEMT process and has an output power capability of 1 W at 1dB gain compression (P-1dB) and a small signal gain of  20dB.



EXHIBITION

Companies booking two or more delegate places are able to take part in the commercial exhibition that accompanies the conference. Please note: there is a maximum of 20 exhibition tables at each meeting, these are offered on a first come basis. Booking two delegate places does not guarantee an exhibition space, please email exhibition@armms.org to check availability and reserve and exhibition space.


SPONSORSHIP

The Society would like to thank Ansys for sponsoring the November 2017 meeting:


CALL FOR PAPERS

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.

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