8,337 research outputs found
Mode-division-multiplexing of multiple Bessel-Gaussian beams carrying orbital-angular-momentum for obstruction-tolerant free-space optical and millimetre-wave communication links
We experimentally investigate the potential of using ‘self-healing’ Bessel-Gaussian beams carrying orbital-angular-momentum to overcome limitations in obstructed free-space optical and 28-GHz millimetre-wave communication links. We multiplex and transmit two beams (l = +1 and +3) over 1.4 metres in both the optical and millimetre-wave domains. Each optical beam carried 50-Gbaud quadrature-phase-shift-keyed data, and each millimetre-wave beam carried 1-Gbaud 16-quadrature-amplitude-modulated data. In both types of links, opaque disks of different sizes are used to obstruct the beams at different transverse positions. We observe self-healing after the obstructions, and assess crosstalk and power penalty when data is transmitted. Moreover, we show that Bessel-Gaussian orbital-angular-momentum beams are more tolerant to obstructions than non-Bessel orbital-angular-momentum beams. For example, when obstructions that are 1 and 0.44 the size of the l = +1 beam, are placed at beam centre, optical and millimetre-wave Bessel-Gaussian beams show ~6 dB and ~8 dB reduction in crosstalk, respectively
Millimetre Wave Power Measurement
There is currently no traceable power sensor for millimetre wave frequencies above 110 GHz. This thesis investigates a novel approach to remove this limitation by combining the placement of a uniquely designed microchip directly in waveguide. The design of the chip is novel in that it does not rely on a supporting structure or an external antenna when placed in the waveguide.
The performance of the design was primarily analysed by computer simulation and verified with the measurement of a scale model. The results show
that it is feasible to measure high frequency power by placing a chip directly in waveguide. It is predicted that the chip is able to absorb approximately 60% of incident power. Any further efficiency would require modification of the chip substrate. However, this proposed design should allow the standards institutes a reference that will enable the calibration of equipment to beyond
110 GHz
Millimetre-wave antennas and systems for the future 5G
Editorial of the special issue on Millimetre-Wave Antennas and Systems for the Future 5
Millimetre-wave and Terahertz Electronics
Overview:
The basic thesis for the advancement of millimetre-wave and terahertz electronics is
represented in four sections: Signal Processing, Component Design and Realization,
Modelling and Materials, and Paradigm Shift. The first section is at system and circuit levels
and reports on complex signal process functions that have been performed directly on the
millimetre-wave carrier signal, intended for realizing low-cost and adaptive communications
and radar systems architectures. The second section is at circuit and component levels and
reports on techniques for the design and realization of low-loss passives for use at millimetrewave
frequencies. The third section is at component and material levels and reports on
modelling techniques for passives for use at both millimetre-wave and terahertz frequencies.
Finally, the fourth section introduces a revolutionary new technology that represents a
paradigm shift in the way millimetre-wave and terahertz electronics (i.e. components, circuits
and systems) can be implemented. As found with the new generation of mobile phone
handsets, a fusion of two extreme technologies can take place; here, complex signal processing
operations could be performed both directly on the carrier signal and with the use of a spatial
light modulator.
Based on a selection of 20 papers (co-)authored by the candidate †b, and published over a
period of 15 years, it will be seen that a coherent theme runs throughout this body of work, for
the advancement of knowledge in millimetre-wave and terahertz electronics
Keynote speech 1: Progress in THz technology enabled by photonics
As THz and millimetre wave technologies are further developing for a range of applications, photonics is one of the key technology for its development. We will discuss the different recent advances in photonic technologies for THz and millimetre wave. In particular we will look at integration technologies and their potential for reduced foot print and lower power consumption. We will although look at the comparative progress of electronic based solutions and discuss the future outlook of both technologies
Temporal and spatial combining for 5G mmWave small cells
This chapter proposes the combination of temporal processing through Rake combining based on direct sequence-spread spectrum (DS-SS), and multiple antenna beamforming or antenna spatial diversity as a possible physical layer access technique for fifth generation (5G) small cell base stations (SBS) operating in the millimetre wave (mmWave) frequencies. Unlike earlier works in the literature aimed at previous generation wireless, the use of the beamforming is presented as operating in the radio frequency (RF) domain, rather than the baseband domain, to minimise power expenditure as a more suitable method for 5G small cells. Some potential limitations associated with massive multiple input-multiple output (MIMO) for small cells are discussed relating to the likely limitation on available antennas and resultant beamwidth. Rather than relying, solely, on expensive and potentially power hungry massive MIMO (which in the case of a SBS for indoor use will be limited by a physically small form factor) the use of a limited number of antennas, complimented with Rake combining, or antenna diversity is given consideration for short distance indoor communications for both the SBS) and user equipment (UE). The proposal’s aim is twofold: to solve eroded path loss due to the effective antenna aperture reduction and to satisfy sensitivity to blockages and multipath dispersion in indoor, small coverage area base stations. Two candidate architectures are proposed. With higher data rates, more rigorous analysis of circuit power and its effect on energy efficiency (EE) is provided. A detailed investigation is provided into the likely design and signal processing requirements. Finally, the proposed architectures are compared to current fourth generation long term evolution (LTE) MIMO technologies for their anticipated power consumption and EE
Multi-Gigabit Wireless Link Development
CSIRO ICT Centre is developing millimetre wave point-to-point links suitable for multi-gigabit wireless connectivity. Suitable spectrum for this purpose is allocated at the 60 GHz band and above. This paper reports a new point-to-point link that will be installed at Marsfield site to demonstrate multi-gigabit operation and performance of its key components. The link will operate at the 81-86 GHz band incorporating CSIRO designed millimetre wave MMICs and multi-gigabit modems
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