Antennas for Mobile and Satellite Communications

One of our traditionally strong areas is antenna design for mobile and satellite. For example, the figure below shows the prototype and current distribution of a dual-element planar inverted-F antenna for compact handheld MIMO terminals, designed together with Sony Mobile (known previously as Sony Ericsson). It is a planar inverted-F antenna (PIFA) operating in the 2.5 GHz band on a 40 mm by 100 mm printed circuit board (PCB), equivalent in size to a typical MIMO handset. The paper reporting this work has been highly cited (60+ citations as of May 2014).

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(a)                                                   (b)                                    

Fig. 1 (a) A dual-element planar inverted-F antenna (PIFA) operating in the 2.5 GHz band. (b) The current distribution of duel-element PIFA.

Fig. 2(a) below is a novel design of a circular polarized antenna for multi-band L-band compact receivers. The design employs the concept of multi-stacked patches fed through a single coaxial probe. The details can be found in our paper. Further to this work, an enhanced design with multiple bands was licensed to SSBV Space & Ground Systems Ltd., and has been embedded on a satellite, as shown in the right figure below.

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(a)

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(b)

Fig. 2 (a) A circular polarized antenna for multi-band L-band compact receivers. (b) Antenna integrated into a satellite.

We have developed a circular-polarization design of the dual-band Dielectric Resonator Antenna (DRA) for indoor access point applications. This is different from the conventional DRA by inserting air gap between the dielectric resonator and the ground plane, which offers more degrees of design freedom and wider bandwidth. The proposed box-matched DRA possesses two wide-band operation modes at 3.36-4.47 GHz (28.3%) and 4.60-6.78 GHz (38.3%), and keeps a 3 dB boresight axial ratio across 3.72-4.25 GHz (13.2%) and 5.45-5.85 GHz (7.08%). Consistent, directional radiation performance and antenna gain (4.7-6.5 dBi) over the two frequency ranges have been obtained. A simple fabrication process is employed, making the proposed DLA a low-cost candidate for indoor access point.

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 Fig. 3 (a) Side view of the box-matched dual-band DRA. (b) Top view. (c) Bottom view, showing the microstrip feedlines. (d) Photographs of the fabricated antenna.

Ultra-Wideband Antennas

State-of-the-art radio systems require antennas that are a) able to cover an ultra-wide range of operating frequency bands, and b) compact and yet robust enough to be mounted in settings that range from satellites to the human body. Our pioneering work in understanding the operation of UWB antennas and systems has led to many publications in highly-cited and world-renowned journals, including the 2005 paper "Study of a printed circular disc monopole antenna for UWB systems", which has been cited more than 550 times, according to Google Scholar (as of May 2014). This paper demonstrated, for the first time, a printed version of the conventional disc monopole UWB antenna.
 
The work has also led to significant contributions to the UK Ofcom Spectrum Framework Review and the developments of new products and business opportunities, new technologies for assessing the EM emission on the mobile handset and for smart meter deployment, and wearable antennas deployed in the battlefield to reduce the load and smart communications for dismounted soldiers. 
 

Photonic Antennas with Integrated Optical Transducers

Distribution of multiple wireless services including GSM/UMTS, TETRA and WLAN via installed fibres in buildings has become a commercial reality because of the broadband, low-loss and modulation format agnostic features that the radio-over-fibre technique offers. Distributing multiple services in a radio over fibre system also centralise the management of telecom and network equipment. Photonic antennas find applications in such in-building scenarios by acting as the interface between the installed fibre infrastructure and the wireless service users. The cost of manufacturing such photonic antennas can potentially be reduced further if they are integrated directly with the optoelectronic components performing the optical-electrical and electrical-optical conversions, and this has been the motivation and the subject of the project.

Photonic Antennas has been a collaborative project between University College London (UCL), Queen Mary University of London (QMUL) and Rutherford Appleton Laboratory (RAL). UCL has been responsible for the design, development and fabrication of the Asymmetric Fabry-Perot Modulator/detector (AFPM) which is used as the key optical transducers functioning simultaneously as an optical intensity modulator and a photodetector. QMUL has been responsible for designing and fabricating a ring of Electromagnetic Bandgap (EBG) and non-EBG patch antennas. RAL has been responsible for developing a technology to package the AFPM from UCL with a connectorised optical fibre pigtail which is critical if the device is to be deployed outside the laboratory environment. RAL has also been responsible for integration of the AFPMs with the antennas from QMUL resulting in the ultimate photonic antennas.

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Whitespace Machine Communication Lab

Some of the research in this theme is organised under the Whitespace Machine Communication (WMC) Lab led by Dr Yue Gao. The lab focuses on developing theoretical research into practice in the interdisciplinary area among antennas, signal processing and white space spectrum for Cyber Physical System (CPS), Machine-to-Machine (M2M) and Internet-of-Things (IoT) applications. Areas of research include:

Check out the lab for up-to-date news, publications and research opportunities, and follow the lab on Twitter.

Highlights and Research Outcomes

Selected Research Grants and Projects

Selected Recent Publications