Steven M.R. Jones

Design of a planar inverted F-L antenna (PIFLA) for lower-band UWB applications

This paper examines the case for an ultrawideband planar inverted-F-L-antenna design intended for use in the lower sub-band. The antenna construction is based on the conventional inverted F, and inverted L as its feed element, and parasitic element, respectively. The optimized antenna size is 30×15×4mm3. The prototype antenna has a good return loss of −10 dB, and a 66.6% impedance bandwidth (2.8 GHz–5.6 GHz), the gain varies between 3.1 dBi and 4.5 dBi.

Indoor millimetre-wave propagation channel simulations at 28, 39, 60 and 73 GHz for 5G wireless networks

Millimeter-wave indoor propagation characteristics including path loss models and multipath delay spread values for systems using directional and omnidirectional antennas are presented. The performance of the four 5G candidate frequencies, 28 GHz, 39 GHz, 60 GHz and 73 GHz, are investigated in line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios using published real time frequency measurements conducted in indoor environments. Comparisons are made against simulation data obtained from the 3D Ray Tracing Wireless InSite software over Tx-Rx separations of 1.5 m to 62 m. In addition, frequency-dependent electrical properties, such as conductivity-σ and permittivity-ε, of common building materials are incorporated in the simulation. Results show material type influences propagation behavior of mm-waves due to reflections, diffractions and penetrations of walls and objects (obstacles). It is also shown that while both, the received power and delay spread decrease with increasing frequency, the number of ray paths increases.

Novel Fractional Wavelet Transform with Closed-Form Expression

A new wavelet transform (WT) is introduced based on the fractional properties of the traditional Fourier transform. The new wavelet follows from the fractional Fourier order which uniquely identifies the representation of an input function in a fractional domain. It exploits the combined advantages of WT and fractional Fourier transform (FrFT). The transform permits the identification of a transformed function based on the fractional rotation in time-frequency plane. The fractional rotation is then used to identify individual fractional daughter wavelets. This study is, for convenience, limited to one-dimension. Approach for discussing two or more dimensions is shown.

A Multi-Antenna Design Scheme based on Hadamard Matrices for Wireless Communications

A quasi -orthogonal space time block coding (QO -STBC) scheme that exploits Hadamard matrix properties is studied and evaluated. At first, an analytical solution is derived as an extension of some earlier proposed QO-STBC scheme based on Hadamard matrices, called diagonalized Hadamard space-time block coding (DHSBTC). It explores the ability of Hadamard matrices that can translate into amplitude gains for a multi-antenna system, such as the QO-STBC system, to eliminate some off-diagonal (interference) terms that limit the system performance towards full diversity. This property is used in diagonalizing the decoding matrix of the QOSTBC system without such interfering elements. Results obtained quite agree with the analytical solution and also reflect the full diversity advantage of the proposed QO-STBC system design scheme. Secondly, the study is extended over an interference-free QO-STBC multi-antenna scheme, which does not include the interfering terms in the decoding matrix. Then, following the Hadamard matrix property advantages, the gain obtained (for example, in 4x1 QO-STBC scheme) in this study showed 4-times louder amplitude (gain) than the interference-free QOSTBC and much louder than earlier DHSTBC for which the new approach is compared with. Original Research Article

Coupling Measurements of an Antenna System Suitable for Relay-Aided WiMAX Network

In this paper two novel antennas, suitable for access and backhaul links, are designed, fabricated and tested for a Relay Station in a WiMAX wireless network. A single modifled E-shaped patch antenna is described, presenting 10dB gain over 12.4% bandwidth. This antenna element is used for the design of a 4 £ 4 planar array which provides experimental gain of 21.2dB. The antenna system on the Relay Station operates at 3.4GHz and includes one single antenna element for access link realization and an antenna array for the backhaul link realization. These antennas are installed in two conflguration arrangements and tested in terms of their radiation performances and coupling efiects. The simulated and measured results are quite satisfactory and in good agreement at which the maximum coupling between the access and backhaul antennas is found below i25dB for all tested cases.

Calculation of the spatial envelope correlation between two antennas in terms of the system scattering parameters including conducting losses

The envelope correlation for a two-element antenna array may be calculated using the antenna radiation fields, or more simply from the scattering parameters of the system. The use of scattering parameters provides a major simplification over the direct use of field data. In this paper we propose a modification of the scattering parameter method which also includes the antenna losses. This approach has the advantage of simplifying the antenna design process, especially when low envelope correlations are needed. It also offers a better prediction of the spatial envelope correlation, and a good framework for understanding the effects of the mutual coupling. The accuracy of this proposed method is illustrated by two examples.