Ayman Abbosh

Flexible and Compact AMC Based Antenna for Telemedicine Applications

We present a flexible, compact antenna system intended for telemedicine applications. The design is based on an M-shaped printed monopole antenna operating in the Industrial, Scientific, and Medical (ISM) 2.45 GHz band integrated with a miniaturized slotted Jerusalem Cross (JC) Artificial Magnetic Conductor (AMC) ground plane. The AMC ground plane is utilized to isolate the users body from undesired electromagnetic radiation in addition to minimizing the antennas impedance mismatch caused by the proximity to human tissues. Specific Absorption Rate (SAR) is analyzed using a numerical human body model (HUGO) to assess the feasibility of the proposed design. The antenna expresses 18% impedance bandwidth; moreover, the inclusion of the AMC ground plane increases the front to back ratio by 8 dB, provides 3.7 dB increase in gain, in addition to 64% reduction in SAR. Experimental and numerical results show that the radiation characteristics, impedance matching, and SAR values of the proposed design are significantly improved compared to conventional monopole and dipole antennas. Furthermore, it offers a compact and flexible solution which makes it a good candidate for the wearable telemedicine application.

Design, Fabrication, and Testing of Flexible Antennas

Their light weight, low-cost manufacturing, ease of fabrication, and the availability of inex‐ pensive flexible substrates (i.e.: papers, textiles, and plastics) make flexible electronics an ap‐ pealing candidate for the next generation of consumer electronics [2]. Moreover, recent developments in miniaturized and flexible energy storage and self-powered wireless com‐ ponents paved the road for the commercialization of such systems [3].

Printed Yagi-Uda array for MIMO systems

In this paper, A Yagi-Uda antenna array consisting of four radiating elements is presented. The array elements are oriented back to back in a cross fashion to achieve a pattern orthogonality utilizing the end-fire radiation characteristics of the Yagi-Uda antennas. This technique is proposed to reduce the mutual coupling between the radiating elements which is essential to the performance of Multiple Input Multiple Output (MIMO) systems. Design and simulations are conducted using CST Microwave Studio which is based on the Finite Integration Technique (FIT). Results show that the correlation level is below -35 dB between the array elements at 5.2 GHz with about λ/4 separation distance.

Mutual coupling reduction between two patch antennas using a new miniaturized soft surface structure

Two patch antenna elements are designed to work at 5.8 GHz frequency. The E-plane mutual coupling between the two antenna elements has been reduced by 10 dB by using a new miniaturized soft surface structure that allows a λ0/2 distance between the patches. The radiation patterns show no significant change in the radiation characteristics, but better directivity, which is expected.

Flexible CPW-IFA antenna array with reduced mutual coupling

In this paper, a flexible and extremely low profile CPW fed Inverted F Antenna (IFA) array is presented. The array consists of two radiating elements which are separated by λ/125 yet exhibit a low mutual coupling (-27dB). This is achieved by creating pattern diversity through defecting the ground plane and adding a parasitic structure. This technique is proposed to reduce the mutual coupling between the array elements which is essential to the performance of Multiple Input Multiple Output (MIMO) systems. Design and simulations are carried out using CST Microwave Studio which is based on the Finite Integration Technique (FIT). Results show that the proposed design is a reasonable candidate for flexible and wearable wireless systems.

Miniaturized Thin Soft Surface Structure Using Metallic Strips with Ledge Edges for Antenna Applications

A new thin electromagnetic soft surface of strips in which ledge edges are used to reduce the strip period width and in turns a miniaturized structure is achieved. The surface is tested to reduce the mutual coupling between microstrip patches separated by a half wavelength in free space (center-to- center). A 20% relative bandgap bandwidth is achieved. The measurements revealed good agreement with the simulated results.

Flexible Yagi-Uda antenna for wearable electronic devices

Mechanical flexibility along with size, weight and cost are among the main challenges for future wearable electronic devices. In this paper, the effects of bending on a planar flexible Yagi-Uda antenna operating at WLAN (IEEE 802.11) 5.2 GHz are reported. The flat antenna achieves a relative bandwidth of 13% over which S11 is less than -10 dB, a realized gain of 8.1 dB, a front-to-back-ratio of 17 dB and a half-power beam width (HPBW) of 89°. The results showed that the antenna maintained the WLAN (5150-5350 MHz) matching bandwidth required under a wide range of bending angles ΨB.

A Compact Dual Band Polyimide Based Antenna for Wearable and Flexible Telemedicine Devices

Recent wearable health monitoring systems use multiple biosensors embedded within a wireless device. In order to reliably transmit the desired vital signs in such systems, a new set of antenna design requirements arise. In this paper, we present a flexible, ultra-low profile, and compact dual band antenna. The proposed design is suitable for wearable and flexible telemedicine systems and wireless body area networks (WBANs). The antenna is inkjet printed on a 50.8µ mP olyimide Kapton substrate and fed by a Coplanar Waveguide (CPW). The proposed design has the merits of compactness, light weight, wide bandwidth, high efficiency, and mechanical stability. The performance of the antenna is also characterized against bending and rolling effects to assess its behaviour in a realistic setup since it is expected to be rolled on curved surfaces when operated. The antenna is shown to exhibit very low susceptibility to performance degradation when tested against bending effects. Good radiation characteristics, reduced fabrication complexity, cost effectiveness, and excellent physical properties suggest that the proposed design is a feasible candidate for the targeted application.

Flexible CPW-IFA antenna for wearable electronic devices

The capability of bending, twisting and folding offered by mechanically flexible films and/or substrates along with size, weight and cost constraints are among the main challenges in future wearable electronic devices. In this paper, the effects of bending on a planar flexible CPW- IFA antenna operating at WLAN (IEEE 802.11) 2.4/5.2/5.8 GHz bandwidths is proposed. The flat antenna achieves a relative bandwidth of 14% (2.25-2.61) GHz and 42% (4.98-7.64) GHz over which S11 is less than -10 dB, and a realized gain of 1.86, 4.21 and 2.94 dB at 2.4, 5.2, and 5.8, respectively. The results show that the antenna maintained the WLAN matching lower and upper bandwidths required under a wide range of bending angles ψB.

Ultra thin printed monopole based UWB antenna with extended 2.45 GHz ISM band operability

A compact Ultra Wide Band (UWB) antenna printed on a 50.8-μm Kapton polyimide Substrate is proposed in this paper. The semi-eliptical based radiating element is fed by a linearly tapered coplanar waveguide (CPW) which provides continuous transitional impedance for improved matching. The proposed design covers the standard UWB range which extends between 3.1 to 10.6 GHz. Furthermore, a T shaped structure is added to give rise to a resonance at 2.45 GHz which encompasses the Industrial, Scientific, Medical (ISM) band.