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James Kelly

Lecturer in Microwave Antennas
MEng (Hons), PhD, PG Cert ULT, MIEEE
+44 (0)1483 689480
Wednesdays 1-2pm


Areas of specialism

Microwave Antennas

University roles and responsibilities

  • Additional Learning Support (ALS) Tutor for Electronic Engineering


Research interests

Research projects

My teaching

My publications


Idris IH, Hamid MR, Jamaluddin MH, Rahim MKA, Kelly JR, Majid HA (2014) Single-, dual- and triple-band frequency reconfigurable antenna Radioengineering 23 (3) pp. 805-811
The paper presents a frequency reconfigurable slot dipole antenna. The antenna is capable of being switched between single-band, dual-band or triple-band operation. The antenna incorporates three pairs of pindiodes which are located within the dipole arms. The antenna was designed to operate at 2.4 GHz, 3.5 GHz and 5.2 GHz using the aid of CST Microwave Studio. The average measured gains are 1.54, 2.92 and 1.89 dBi for low, mid and high band respectively. A prototype was then constructed in order to verify the performance of the device. A good level of agreement was observed between simulation and measurement.
Borja A, Kelly JR (2015) Reconfigurable Microwave Circuit Based on a Single Triangular Microstrip Patch 2015 IEEE INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION & USNC/URSI NATIONAL RADIO SCIENCE MEETING pp. 2253-2254
Kelly JR, Borja AL (2014) Hardware block for use in programmable microwave function arrays Electronics Letters 50 (15) pp. 1076-1077
Ultimately, the research presented will lead to the development of a microwave integrated circuit that is analogous to a field programmable gate array. An early step towards the development of this technology is presented. Specifically, a 3-port device, based on a single resonant element, namely a microstrip square patch, is described. The device operates simultaneously as a filter and an antenna. Filter performance is obtained between ports 1 and 2. Antenna performance is obtained on port 3. © 2014 The Institution of Engineering and Technology.
Wang Z, Kelly JR, Hall PS, Borja AL, Gardner P (2014) Reconfigurable parallel coupled band notch resonator with wide tuning range IEEE Transactions on Industrial Electronics 61 (11) pp. 6316-6326
This paper presents a new form of reconfigurable band notch resonator with a wide tuning range. The whole structure consists of a through line and two parallel coupled resonators. This paper presents an accurate lumped element equivalent circuit for the parallel coupled resonator. The mechanism giving rise to the wide tuning range is also investigated. The first harmonic of the fundamental stop-band is analyzed and compared with that of the varactor-coupled resonator. Measurement results show that the stop-band of the filter can be tuned from 0.6 to 4.0 GHz. This is achieved by varying the capacitance of two pairs of varactor diodes. The stop-band tuning range is restricted by the capacitance variation which can be achieved using the varactor diode. The potential tuning range of a filter based on this resonator is greater than one decade. © 1982-2012 IEEE.
Wei JD, Chen XZ, Kelly JR, Cui YZ (2015) Blast furnace stockline measurement using radar IRONMAKING & STEELMAKING 42 (7) pp. 533-541
Kelly JR, Borja A (2015) Reconfigurable Microwave Circuit Based on Three Triangular Microstrip Patches 2015 IEEE INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION & USNC/URSI NATIONAL RADIO SCIENCE MEETING pp. 2251-2252
Chen G, Xiao P, Kelly J, Li B, Tafazolli R (2017) Full-Duplex Wireless-Powered Relay in Two Way Cooperative Networks IEEE Access 5 pp. 1548-1558
This paper investigates a full duplex wirelesspowered two way communication networks, where two hybrid access points (HAP) and a number of amplify and forward (AF) relays both operate in full duplex scenario. We use time switching (TS) and static power splitting (SPS) schemes with two way full duplex wireless-powered networks as a benchmark. Then the new time division duplexing static power splitting (TDD SPS) and full duplex static power splitting (FDSPS) schemes as well as a simple relay selection strategy are proposed to improve the system performance. For TS, SPS and FDSPS, the best relay harvests energy using the received RF signal from HAPs and uses harvested energy to transmit signal to each HAP at the same frequency and time, therefore only partial self-interference (SI) cancellation needs to be considered in the FDSPS case. For the proposed TDD SPS, the best relay harvests the energy from the HAP and its self-interference. Then we derive closed-form expressions for the throughput and outage probability for delay limited transmissions over Rayleigh fading channels. Simulation results are presented to evaluate the effectiveness of the proposed scheme with different system key parameters, such as time allocation, power splitting ratio and residual SI.
Uchendu I, Kelly JR (2017) Ultrawide isolation bandwidth Compensated Power Divider for UWB applications Microwave and Optical Technology Letters 59 (12) pp. 3177-3180
This article presents design analyses for achieving an ultrawide isolation bandwidth compensated power divider (CPD). The CPD offers improvement in complexity, size and insertion when compared with alternative techniques for increasing isolation bandwidth. A prototype CPD with -15dB isolation bandwidth of 114% was fabricated and measured to validate the analyses.
Wang Z, Hall P, Kelly JR, Gardner P (2017) Wideband Frequency Domain and Space Domain Pattern Reconfigurable Circular Antenna Array IEEE Transactions on Antennas and Propagation 65 (10) pp. 5179-5189
This paper presents a wideband circular antenna array with a frequency domain and space domain reconfigurable radiation pattern. A wideband circular array antenna is designed with omni-directional radiation pattern, in azimuth direction, throughout the whole frequency band. The antenna array consists of eight TEM horn antennas. The antenna array exhibits an omni-directional azimuthal radiation pattern when all eight ports are excited with signals of the same magnitude and phase. The antenna array is fed through eight reconfigurable bandstop filters and a power splitter. This enables it to provide an omni-directional azimuthal pattern along with a single directional pattern null in a given spatial direction and at a certain frequency. Both the spatial direction and the frequency can be altered. The antenna works from 0.8 GHz to 3.0 GHz. The antenna array will be useful in combating interference in wideband communication systems. It will also be of value in surveillance military applications.
da Costa I, Filgueiras H, Kelly J, Arismar Cerqueira S, Xiao P (2018) Mechanical Beam Steering Circular Patch Antenna EuCAP 2018 Proceedings
This work reports preliminary results and a
prototype of an innovative mechanical beam steering circular
patch antenna for 5G indoor cellular access networks with sub6
GHz operation. The beam steering is achieved using 18 screws
installed around the circular patch radiator, working as a
reflector by proper managing the screws position and height.
The new antenna can steer its main beam over 360º in azimuth
plane and from -30º to 30º in the elevation plane with gain up to
8.01 dBi at 4.6 GHz.
Allayioti M, Kelly J, Mittra R (2018) Beam and Polarisation Reconfigurable Microstrip Antenna Based on Parasitics Microwave and Optical Technology Letters
This paper presents a dual-notch polarization and beam reconfigurable microstrip antenna. It uses parasitics which incorporate switches to steer its beam away from boresight and dual-notches which, again, incorporate switches to reconfigure between linear and circular polarization. The antenna is a low profile microstrip patch antenna which only uses a single feed, allowing it to be compact and simple in terms of its structure.

Additional publications