In this letter, we present a compact ultrawideband (UWB) antenna printed on a 50.8-μm Kapton polyimide substrate. The antenna is fed by a linearly tapered coplanar waveguide (CPW) that provides smooth transitional impedance for improved matching. The proposed design is tuned to cover the 2.2-14.3-GHz frequency range that encompasses both the 2.45-GHz Industrial, Scientific, Medical (ISM) band and the standard 3.1-10.6-GHz UWB band. Furthermore, the antenna is compared to a conventional CPW-fed antenna to demonstrate the significance of the proposed design. A parametric study is first performed on the feed of the proposed design to achieve the desired impedance matching. Next, a prototype is fabricated; measurement results show good agreement with the simulated model. Moreover, the antenna demonstrates a very low susceptibility to performance degradation due to bending effects in terms of impedance matching and far-field radiation patterns, which makes it suitable for integration within modern flexible electronic devices.

A Compact Polyimide-Based UWB Antenna for Flexible Electronics

A compact hexagonal Sierpinski fractal antenna for super wideband applications is presented. It consists of hexagonal radiation patch with two iterations of Sierpinski square slots and coplanar waveguide feeding. An impedance bandwidth of 3.4–37.4 GHz is achieved. The achieved bandwidth ratio is 11:1. Desirable radiation performance characteristics including relatively stable and omni-directional radiation patterns are obtained over this range. A good agreement is achieved between the simulated and experimental results. The designed antenna has advantages of wider bandwidth and miniaturised size over the previously reported structures.

CPW-fed hexagonal Sierpinski super wideband fractal antenna

This letter presents a highly isolated compact four-element planar ultrawideband (UWB) multiple-input-multiple-output (MIMO) antenna array configuration. The main advantages of the proposed array configuration are that it requires no isolation/decoupling circuit and the configuration is easily extendable to larger size array. The array consists of novel miniaturized slotted annular ring monopole antenna and each element in the array is placed orthogonal to its adjacent elements. The fabricated structure provides good impedance bandwidth matching and high isolation between elements over the range from 3 to 15 GHz. The absence of decoupling circuit results in overall compact size of the proposed design. The prototypes are fabricated and tested. The simulated and measured results are in good agreement. Moreover, the envelope correlation coefficient and channel capacity loss of the array are calculated, which shows good MIMO performance. The proposed monopole antenna structure supports multielement UWB MIMO antenna array design with easy extension of elements and without any decoupling circuit. An example of eight-element array is also investigated.

Easily Extendable Compact Planar UWB MIMO Antenna Array

A novel and compact super wideband (SWB) exponentially tapered feed region and patch printed monopole antenna is proposed. This antenna is fed by a 50-Ω triangular tapered feed line. The antenna operates over a bandwidth of 2.5-80 GHz with a return loss of 10 dB or more. The dimensions of the proposed antenna are 40 × 30 × 1.6 mm 3 . An exponential curve is employed in the feed region and a triangular tapered feed line is used. The ground plane feed gap is optimised to 1.3 mm. The proposed tapered monopole antenna has demonstrated an ultra-large bandwidth with satisfactory radiation properties. Two particular antennas are examined, one with a rectangular feed line and another with a triangular tapered feed line. The performance of the antenna in frequency domain is investigated, and a good agreement is achieved between the simulation and experimental results. In addition, the time domain characteristics of the proposed antenna are evaluated experimentally. This antenna can be used in ultra-wideband or SWB applications.

https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/iet-map.2013.0094

Printed monopole antenna with tapered feed line, feed region and patch for super wideband applications

The demand for flexible and wearable wireless systems is increasing exponentially in today's information-oriented society. These systems are extremely beneficial and applied in a wide spectrum of fields, such as personal communication, medicine, military, firefighting, entertainment, aeronautics, and radio frequency identification. In this paper, the design constraints, fabrication process, flexibility tests, and measurement of flexible and wearable antennas are discussed in detail. Furthermore, the design, fabrication, and testing of a compact flexible ultrawideband antenna are presented. The proposed design has the merits of light weight, ultralow profile (50.8 μm), wideband width, mechanical robustness, compactness, and high efficiency. The antenna is also tested against bending effects to characterize its performance in a realistic setup since it is expected to be conformed on curved surfaces and/or flexed during operation.

Design and Fabrication of Compact Inkjet Printed Antennas for Integration Within Flexible and Wearable Electronics

Circular disc monopole antennas are investigated for current and future ultrawideband (UWB) applications. The studied antennas are compact and of small size (25 mm × 35 mm × 0.83 mm) with a 50-Ω feed line and offer a very simple geometry suitable for low cost fabrication and straightforward printed circuit board integration. More specifically, the impedance matching of the classic printed circular disc UWB monopole is improved by introducing transitions between the microstrip feed line and the printed disc. Two particular designs are examined using a dual and single microstrip transition. By using this simple antenna matching technique, respective impedance bandwidths (|Sn | <; -10 dB) from 2.5 to 11.7 GHz and 3.5 to 31.9 GHz are obtained. Results are also compared to a classic UWB monopole with no such matching network transitions. Measured and simulated reflection coefficient curves are provided along with beam patterns, gain and group delay values as a function of frequency. The transient behavior of the studied antennas is also examined in the time domain.

M. N. Srifi

Papers

Compact Disc Monopole Antennas for Current and Future Ultrawideband (UWB) Applications