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A technique for enhancing the bandwidth of a broadside tri-modal patch antenna is described. The key idea of the technique is to incorporate a dual-resonance structure into the broadside tri-modal patch geometry. By increasing one edge of the tri-modal patch while decreasing its size at the opposite edge, the resulting structure can be viewed as two superimposed Y-shaped structures of different resonant frequencies. This intuition is confirmed using characteristic mode analysis (CMA). Furthermore, guided by CMA, further modifications enable two sets of resonant modes to be tuned for increasing the bandwidth of the tri-modal patch antenna. Importantly, the proposed bandwidth enhancement technique does not affect the desired broadside radiation patterns significantly. Therefore, it can be utilized to modify the tri-modal patch antenna without degrading its potential for massive MIMO array application. Measurement results show that the technique enhances the 10 dB impedance bandwidth from 4.3% to 19.7% with the largest antenna dimension of $0.48{\lambda _{c}}$ , where ${\lambda _{c}}$ is the wavelength in air at the center frequency. The design example of the proposed technique is able to cover widely used 3 GHz bands in 5G communication systems and its potential usage in massive MIMO arrays is demonstrated.

We developed an in-silico model of cancer growth to investigate the extent to which metabolic switching occurs in tumour masses. Cancer therapies based on glycoconjugation, the linking of a drug to glucose or another sugar, allow improved selectivity and targeting, thus reducing harmful side effects. This mechanism exploits the over-expression of glucose membrane transporters, a phenotypic alteration in cancer cells included in an array of metabolic alterations known as the Warburg effect. However, the extent to which tumour masses adopt the Warburg phenotype is unclear, potentially limiting the efficacy of therapies based on glycoconjugation. We simulated multiple “what-if” scenarios, each modelling increasing proportions of tumour populations that adopted the Warburg phenotype, and compared the results to the expected growth curves derived from laboratory studies. Our results suggest that the Warburg phenotype is prevalent in tumours, with the population of cancer cells adopting this phenotype significantly outnumbering that of cells that do not.

In this paper, the design considerations for feeding dual-port microstrip square-ring antenna are discussed. In particular, the antenna is evenly divided into eight sectors for analysis with the aid of characteristic modes and electric nearfields. The results can be used to guide the design of the excitation configuration for two ports with low mutual coupling for the square-ring antenna. The rotational and mirror symmetry of eight sectors helps simplify the investigation. The results from characteristic mode analysis (CMA) have also been validated in full-wave simulation with different two-port combinations.

The wireless revolution has created a mobile information society. One key element in this revolution has been the use of RF waves for information transmission. RF waves can be used directly for transmission but it is also possible to harness RF waves that are already in use for other applications. These existing RF waves can be thought of as ambient RF waves or signals and can be harnessed for a wide variety of applications. Using sunlight as an analogy, for ambient RF waves, we can deduce that applications such as cameras, navigation, solar cells, heliostats and heliographs can be readily carried over to ambient RF waves in the form of imaging, device free location estimation, ambient RF energy harvesting, reconfigurable intelligent surface (RIS) and ambient backscatter communication (AmBC). In this paper we explore technologies and techniques that can harness ambient RF waves for our benefit, without adding further RF transmissions to the environment. In essence we treat the harnessing of ambient RF waves as a single research area rather than a collection of unrelated applications. This allows us to explore and develop new and novel applications. It also allows us to focus on the fundamental phenomena and applications of ambient RF waves.

This paper presents a combination of machine learning techniques for slip detection in grasping, based on temporal features collected by low-cost tactile sensors. A slippage is an event that is subsequent to prior micro-slippages that have occurred at hand-object contact. The method is based on the application of a sequential classification technique (a variant of recurrent neural networks known as long short-term memory networks or LSTMs), whereby time-series pressure readings from tactile sensors are classified as either slip or non-slip events. We also propose a novel method for autonomous labelling, removing the need for humans in the labelling process. Lastly, this paper proposes a new design for an adaptable wearable tactile sensing device that integrates non-expensive sensors. Our proposed method achieved high accuracy in the classification of slip and non-slip events, obtaining over 95% in offline classification and 89% in online classification using a Sawyer robot.

In this work we describe our investigation into the performance of coherent orthogonal frequency division multiplexing (OFDM) and differentially coherent OFDM communication systems in a wideband waveguide channel consisting of a steel pipe filled with static water. The channel transfer function was measured by a vector network analyzer, and the channel noise (found to be normally distributed above 10 kHz) was measured by a hydrophone connected to a data acquisition device. The measured steel-pipe water channel together with additive complex Gaussian noise is used as the communication channel. Bit error rate (BER) simulation results show that coherent OFDM outperforms differentially coherent OFDM because it takes advantage of accurate channel estimation. Nonetheless, differentially coherent OFDM detection performs well when the sub-carrier separation is less than the coherence bandwidth, offering the benefit of lower system complexity and increased throughput efficiency.

The reverse leakage current in the rectifier is a key challenge in the design of RF energy harvesting (RF-EH) systems, especially in harvesting modulated RF signals from WLAN band. In this paper, we propose a dual-band energy harvesting system operating at GSM-900 (900 MHz) and WLAN (2.4 GHz) bands. To harvest the RF energy from the WLAN band more efficiently, an event-triggered 1:2 parallel-series switched-capacitor (SC) converter is proposed to reduce the reverse leakage current. Meanwhile, this SC converter can provide an output voltage bootstrapping function while maintaining an ultra-low-power consumption down to 28 nW by asynchronous control. The power management unit (PMU) with the rectifier is fully integrated in a CMOS 130-nm process. Measurement results have shown the PMU can boost up the output voltage by 1.73× with an input voltage as low as 0.2 V. When harvesting the modulated waveform, the RF-EH system output ripple is decreased by 6×, and reverse leakage current reduction is over 2500 × compared to the direct connection condition.

The performance of a reconfigurable pixel antenna operating at 27 GHz is investigated in this paper. With different states of hardwired connection, the proposed pixel antenna can achieve a beam scanning range of 240° in the azimuth plane with 6.6-8.9 dBi realized gain. When all hardwired connections are replaced by PIN diode switching, the scanning range and realized gain reduce to 120° and 4.5-7.5 dBi respectively. The antenna efficiency is also decreased to around 65% from over 90%. It is concluded that, more efficient RF switches should be studied for use in in future millimeter-wave reconfigurable pixel antennas.

Radio tomographic imaging (RTI) is a localization technique that can estimate the position of an object on the basis of the received signal strength indicator (RSSI) acquired by WiFi or other wireless networks. In this paper, we demonstrate the RTI approach by utilizing full electromagnetic simulations of an indoor environment. In particular, we consider dielectric cylinders with varying permittivities but fixed radius in which 20 WiFi nodes are deployed on the perimeter (6 m by 3 m) of a room to perform RTI. RTI based on the line-of-sight (LOS) weighting model with total variation based regularization was then used to demonstrate device-free localization. The results indicate that device-free location is possible, even for very high permittivities of greater than 30, motivating further future investigations.

IEEE 802.11ax systems will appear in the market soon and bring significant advancements to existing WLAN technologies. To further enhance their system performance, this paper proposes a planar reconfigurable antenna inspired by the Yagi-Uda structure. It is capable of beam steering by utilizing a switched pixel structure to change the antenna current distribution. Combined with system channel state information the antenna beam direction can be steered towards an active user in order to maximize the gain and therefore improve channel throughput. Simulation and experimental results show that the proposed antenna has an impedance bandwidth from 4.6 to 6.0 GHz (26.4%) and achieves a 300°scanning beamwidth with realized gain up to 9.2 dBi.

The design of a broadband transparent antenna integrated with an indoor solar cell for WLAN communication systems is described. The transparent patch antenna is realized using two layers of copper mesh with micron-sized linewidth. Measurement results show that a broad bandwidth of 20% covering the WLAN band from 4.8 to 5.9 GHz and a uni-directional radiation pattern with backlobe and cross-polarization below −20 dB can be achieved. By utilizing a transparent copper mesh ground on top of the solar cell, a good antenna gain of up to 7 dBi can be achieved. We also utilize two methods to evaluate the transparency of the proposed antenna and it is found to be at least 83%.

A method for implementing continuous tunable load-modulated multiple-input multiple-output (LM-MIMO) transmitters is proposed and investigated. A T-type configuration for the loading network is considered for the load modulator (LM) design, in which a closed-form expression for the load values is also derived for arbitrary constellations. The lumped element topology of a continuous tunable LM is also provided. Simulation results show that the proposed continuous tunable LM is able to handle phase modulation on a hypersphere (PMH).

A high scanning rate circular polarization leaky-wave antenna fed by allpass filter is proposed. It characterizes large scanning rate and circularly polarization in the applicable frequency band. Cascaded 90 degree crossed slots and allpass filter are employed to produce circular polarization and beam steering. The group delay of allpass filter can be engineered in order to enhance the scanning rate. Simulated results indicate a scanning range from 35 degree to 65 degree, which scanning rate of 300 degree/GHz, and axial ration is below 3dB in 100MHz.

A flexible frequency reconfigurable antenna using liquid crystal (LC) is investigated. The antenna consists of a patch with silver ink printed on inner surfaces of two Polyethylene terephthalate (PET) films to form the radiating element and the ground plane. Three cavities filled with LC molecules are then created between the two silver ink layers. Radiation patterns, gains and efficiencies are also reported with and without a biasing voltage. In addition to the experimental results, simulations for the LC based antenna characterization are also provided. Although the demonstrated example does not meet the requirements for useful applications at 5 GHz range, it provides a proof-of-concept demonstrating the possible use of LC in the design of flexible reconfigurable antennas.

In this work we consider the one-dimensional (1D) inverse scattering problem of super-resolving the location of discrete point scatters satisfying the 1D Helmholtz equation. This inverse problem has important applications in the detection of shunt faults in electrical transmission lines and leaks in water pipelines where usually only low frequency spectral information is available from measurements. We formulate the inverse scattering problem as a sparse reconstruction problem and apply convex optimization to super-resolve the location of point scatters. We extend previous results and prove that we can super-resolve up to 4 points and 5-18 points with infinite precision if the points are separated by 1/(2f c ) and 1/f c respectively (f c is the maximum frequency we can measure). This is over 4 times closer than previous results. Simulation results are used to demonstrate the effectiveness of the approach.

A surface waveguide (SWG) leaky-wave antenna for directional single-side beam scanning is presented in this paper. A novelty of this design is periodically removing one-sided unit cells of the SWG to obtain $n=-1$ space harmonic mode, which can transform the guided surface wave into radiated leaky wave and realize single side beam scanning. In addtion, An efficient spoof surface plasmon (SSP)-based transition is utilized to excite the surface wave from conventional coplanar waveguide (CPW). The whole transition consists of one ground-tapered CPW and SSP structures. Because SSP and SWG have the similar transmission mode, SSP structures work as an intermedia to improve the whole transition performance from CPW to SWG. The simulated results show that the transition exhibits low loss and broadband properties. And the average gain of proposed antena is up to 10.5 dB with overall 0.82 radiation efficiency in the range from 10 GHz to 15 GHz. The one-sided directional bean scans from $\varphi=135^{\circ}$ to $\varphi=85^{\circ}$ . The total scanning angle is 50°.

We describe techniques for using multiport antennas in rectennas suitable for ambient RF energy harvesting. Two antenna combining approaches, RF and dc combining, are briefly reviewed. Four impedance matching techniques, MCM, SOM, MLM, and SPM are also reviewed to show how impedance matching can compensate for the negative impact of mutual coupling in compact multiple antenna systems. Making use of these results three multiport rectenna design examples are also provided to show the benefit of using multiport rectenna to increase harvested RF energy. Using this multiport rectenna approach harvested ambient RF energy can exceed 10 µW in some environments, making them suitable for low power Internet of Things devices.

Recent progress on bioresorbable and biocompatible miniature systems provides prospects for developing novel nanobots operating inside the human body. These nanoscale systems are expected to dissolve in vivo and cause no side effect after completing their tasks. Motivated by these advancements, we have developed the analytical framework of touchable communication (TouchCom) to describe the process of targeted drug delivery (TDD) using physically transient nanobots. Built upon our previous work, we develop a novel latticed channel model of TouchCom for an interconnected capillary network near a targeted tumor area. Specifically, we propose a two-dimensional grid to synthesize the microcirculation environment, which is used to describe the propagation process of nanobots. Based on this model, we consider the influence of blood pressure on the efficiency of TDD, and introduce a compensation strategy with the help of an external guiding field to mitigate the misalignment between the direction of blood pressure and the tumor location.

A design for a dual-band transparent coplanar patch antenna for WLAN systems is described. The transparent coplanar patch antenna is constructed by using copper mesh of micron-sized linewidth. Measurement results show that the proposed antenna operates from 2.36 to 2.76 GHz and from 4.92 to 6 GHz covering the WLAN bands and it has a omnidirectional radiation pattern. Compared with other transparent antenna, the proposed antenna has a good total antenna efficiency of up to 45% using the copper mesh film. We also evaluate the transparency and have achieved a high transparency of 92%.

In this paper, integration of a wireless communication system with an illumination system is proposed. A transparent radiator is designed on an illumination cover surface which allows visible light to pass through and to transmit and receive radio frequency (RF) signals simultaneously. A transparent single patch antenna and antenna array have both been considered. Possible applications include smart lampposts, headlights of automobiles (vehicle-to-vehicle communications) or helmets for providing data services and illumination at the same time.

We propose a novel communication-inspired model of contagion phenomena and mitigation strategies by establishing the one-to-one correspondence between the essential components comprising information transmission and epidemic spreading. We then present the notions of normalized ensemble-average prevalence (NEAP) and prevalence delay profile (PDP) to characterize the relative impact and time difference of all the epidemic spreading paths, which are analogous to the classical description methods of path loss and power delay profile in communications. The proposed framework provides an intuitive, coherent, and efficient approach for characterization of the disease outbreaks by applying the well-established communication theories as the analytical lens.

Arabic calligraphy is one of the great art forms of the world. It displays Arabic phrases, commonly taken from the Holy Quran, in beautiful two-dimensional form. The use of two dimensions, and the interweaving of letters and words makes reading a far greater challenge for Artificial Intelligence (AI) than reading standard printed or hand-written Arabic. To approach this challenge, we have constructed a dataset of Arabic calligraphic letters, along with a corresponding corpus of phrases and quotes. The letters dataset contains a total of 3,467 images for 32 various categories of Arabic calligraphic-type letters. The associated text corpus contains 544 unique quoted phrases. These data were collected from various open sources on the web, and include examples from several Arabic calligraphic styles. We have also undertaken both an explorative statistical analysis of this data, and initial machine learning investigations. These analyses suggest that combining knowledge of a limited variety of Arabic calligraphy texts, with a successful machine will be sufficient for the machine reading of forms of Arabic calligraphy.

A novel communication scheme called touchable communication (TouchCom) in the nanoscale and molecular communication area has been recently proposed, which is centred around controllable and trackable message carriers. A potential application scenario of TouchCom in the medical field is targeted drug delivery (TDD), which utilizes physically transient nanobots as vehicles to deliver drug particles. In the TouchCom-inspired TDD system, the loading/injection and unloading of the drug particles correspond to the transmitting and receiving processes, respectively. The nanobots are message carriers and their swimming paths in the vascular tree are the communication channel. The targeted cancerous tissue corresponds to the receiver. Built upon our previous work, we propose a multi-input-multi-output (MIMO) system model for application of TouchCom in TDD in this paper. We draw on the experience of the MIMO structure in traditional wireless communication systems to create a similar MIMO model in TDD system. Moreover, we propose an optimization mechanism for this MIMO framework and present a novel method to assess the corresponding system performance.

In this paper a planar yagi antenna with beam-steering capability for high gain application is presented. A key performance highlight of the antenna is its ability to beam steer through 120° in the azimuth plane without using any phase shifters. The beam steering technique is demonstrated by using an antenna structure consisting of a printed half-wavelength driven element, a ground plane as a reflector, three directors and finally a rectangular grid of parasitic pixels placed directly in front of the directors and in the same layer. The adjacent pixels can be connected/disconnected by means of switching resulting in reconfigurability in beam-direction. The proposed antenna is capable to steer the end-fire beam radiation from −60° to +60°, in xy-plane (θ=90°). The bandwidth of the proposed antenna is approximately 200 MHz (8.2%) around the center frequency of 2.45 GHz with measured peak gains of 7.8–9.8 dBi. The designed antenna has been fabricated and measured to validate the results obtained by the theoretical analyses, genetic optimizations and simulations. Both simulation and experimental results has been provided.

A novel communication scheme called touchable communication (TouchCom) in the nanoscale and molecular communication area has been recently proposed. It is focused on the controllable and trackable properties of message carriers. A potential therapeutic application of TouchCom is the targeted delivery of drugs which utilizes physically transient nanobots as vehicles to deliver drug particles. Meanwhile, the IEEE 1906.1 group, an IEEE standards working group for developing a common framework for nanoscale and molecular communications, has proposed a new standard to IEEE Communications Society Standards Development Board which has been approved recently. This paper maps the paradigm of TouchCom for drug delivery systems into the 1906.1 framework. It also describes the nanoscale simulation package for the Network Simulation 3 (NS-3) platform that implements the IEEE 1906.1 standard, to build a TouchCom example module.

In this paper we present a design for a broadband L-probe microstrip patch rectenna for ambient RF energy harvesting. The broadband L-probe microstrip patch antenna can receive ambient RF signals from UMTS-2100 band (2110–2170 MHz) and WLAN band (2400–2500 MHz) to harvest energy. We provide simulation and measurement results of the broadband L-probe microstrip patch antenna. We also provide results for a dual-band rectifier working in the UMTS-2100 band and WLAN band which is also optimized.

In this paper an optically transparent dual-band antenna is proposed. The antenna can be directly constructed on the surface of display screens for applications in smart watches, tablets and smart TVs. This design approach would relieve the antenna designer of having to integrate antennas into the body of electronic devices and allow them to integrate antennas into the display and provide significant advantages in small form factor and low profile wireless communication apparatus. It is shown that the proposed antenna can exhibit dual-band operation.

In this paper we provide a 2.45-GHz pixel rectenna design for wireless power transmission. We propose a deterministic optimization method called Mixed Integer Linear Programming (MILP) to optimize the pixel antenna. The global optimal hardwire of the pixel antenna is simulated, fabricated, and measured. An optimized 2.45-GHz rectifier is also proposed and simulated in this paper