Dual-band Wireless Applications Research Articles

A Dual-Band Magnetoelectric Monopole Antenna Array Using Mode-Composite Waveguides

A novel substrate-integrated mode-composite waveguide owing two bands where only the quasi-TE10 mode is supported is presented. The waveguide geometry completely shared in the two bands is equivalent to one transmission channel at low frequencies and a pair of individual channels at high frequencies. With the aid of the waveguide, a dual-band magneto-electric (ME) monopole array with a relatively large frequency ratio is designed, fabricated and tested. Benefitting from the shared radiation structure that separately operates as 1 × 2 and 1 × 4 arrays in the low and high frequency bands, satisfying radiation features are obtained simultaneously in the two bands from 10.3 to 11.7 GHz and from 31.8 to 38.1 GHz. The proposed mode-composite waveguide and antenna array are valuable to emerging dual-band wireless applications operating at both microwave and millimeter-wave frequencies.

Performance of wearable circularly polarized antenna on different high frequency substrates for dual-band wireless applications

This paper proposes the effect of different dielectric constants to construct a microstrip patch antenna deployed on Jean's textile covering military wireless applications. Initially, the structure is designed with double L-shaped slits inserted on both sides of the patch with an FR4 dielectric constant of 4.4. Antenna dimensions are 40 ? 25 mm2, which is miniature compared to the wave's length (?) at the desired operating frequency. The proposed antenna performance in terms of simulated parameters such as gain in dBi, reflection loss (S11), directivity, and patch antenna radiation efficiency are executed by the CST MW EM simulator. However, the conventional way of this design with FR4 may not be so reliable when it is designed on Jean's substrate. Besides all the above parameters extracted from the simulator should hold a low value to implement a high-performance deployed wearable antenna. The paper's outcome shows the importance of simulations and measurements undertaken for the proposed antenna assuming both the dielectric constants of FR4 and Jeans cloth material (with ?r of 1.7). The main contribution of the antenna is to resonate at the frequencies of 3.17 GHz with circular polarization and 5.04 GHz with linear polarization. The antenna prototype is described, and its performance is validated using measurements. The proposed structure also provides a better enhancement in terms of 10-dB impedance bandwidth, with an average gain of 5 dBi.

Garuda Vyuha based Microstrip patch antenna structure with high-gain for dual-band wireless applications

In this paper, a high-gain dual-band planar Microstrip patch antenna is designed to work at two different frequencies namely 5.6GHz and 7.4GHz. The antenna structure is in the form of Garuda Vyuha and has high directivity. The results propose that the Garuda Vyuha based antenna structure has very low profile and good polarization characteristics. The proposed antenna structure is simulated using ADS software and from the simulated results, the return loss is -15.094dB at 5.681GHz and -12.371dB at 7.337GHz. The Antenna operates at a bandwidth of 22MHz at 5.6GHz and 41MHZ at 7.4GHz. The Antenna provides a directivity of 5.921 at 5.6GHz and 6.2 at 7.4GHz. This antenna structure can be used for dual band applications in Wireless systems operating in these bands.

A Rectangular Microstrip Patch Antenna for Dual Band Wireless Applications

Background: In this paper, the design of a dual-band microstrip patch antenna with operating frequencies of 2.16 GHz and 2.79 GHz is proposed. Methods: The proposed antenna design is based upon the defected ground structure and rectangular patch with corner cuts. The presented antenna structure is simulated and optimized using CST microwave studio software. Results: The antenna resonates at 2.16 GHz and 2.79 GHz. The bandwidth of the proposed antenna is 2.08 GHz-2.25 GHz at center frequency 2.16 GHz and is 2.7 GHz-2.87 GHz at center frequency 2.79 GHz. The optimized antenna model is fabricated and measured. The measured and simulated results are presented and discussed. The proposed antenna provides a maximum gain of 4.463 dB and the maximum directivity of 5.846 dBi. The maximum radiation efficiency and total efficiency of the antenna are 79.85% and 69.01%, respectively. Conclusion: The proposed antenna is suitable for dual-band wireless applications.

A Cantor Fractal Based Printed Monopole Antenna for Dual-band Wireless Applications

Cantor fractal geometry and its variants are found attractive for microwave antenna designers seeking for compact size multiband antennas. This paper presents the design of a new microstrip fed printed monopole antenna for use in dual-band wireless applications. The radiatingelement of the monopole antenna is in the form of Cantor fractal geometry of the second iteration as applied on rectangular patch. The monopole radiating element has been etched on a substrate with relative permittivity of 4.4 and 1.6 mm thickness and is fed with a 50 ohm microstrip line. A reduced ground plane has been etched on the reverse side of the substrate. Modeling and performance evaluation of the proposed antenna have been carried out using the commercially available EM simulator, IE3D. Simulation results reveal that the proposed antenna offers dual-band resonant behavior with –10 dB impedance bandwidths and radiation characteristics suitable for almost most of the recently available services in the 1-6 GHz range. A parametric study has been carried out to explore the effect the aspect ratio of the proposed antenna radiating element on its performance. The study reveals that the radiating element aspect ratio has a considerable effect on the coupling of the two resonant bands. Besides the simple design, the antenna offers reasonable radiation characteristics. Simulated–10 dB impedance bandwidths for the lower and the upper resonant bands are (2.30–2.84 GHz) and (5.56–6.01 GHz) respectively. This makes the proposed antenna suitable to cover numbers of operating bands of the wireless communication systems (2.4 GHz-Bluetooth, 2.4 GHz ISM, 2.5/5.8 GHz-WLAN, 5.8 GHz-ITS).

Design of Small-size and Low-loss LTCC Filters on Capacitively Loaded Cavities

Design of microwave filters for portable electronics is complicated by conflicting requirements to be met simultaneously such as high selectivity, low insertion loss and compact size. Substrate integrated waveguide (SIW) technology allows designing low-profile high-Q resonators and low-loss bandpass filters based thereof. However, SIW filters are not well-suited for telecommunication applications because of remarkably large size in plane. The size of a SIW cavity can be dramatically reduced by a capacitive loading. Capacitively loaded cavities (CLCs) operating in the TM110 mode can be as small as 1/8 of the guided wavelength and even smaller, i.e. comparable in size with lumped-element resonators. Although the unloaded Q-factor decreases proportionally to cavity size, miniaturized CLCs can exhibit much higher Q-factor than that of lumped-element resonators. This paves the way for designing small-size and low-loss filters for wireless communications and different applications. Miniaturized capacitively loaded SIW cavities are favorably implemented by means of the low temperature co-fired ceramics (LTCC) technology. The goal of the paper is to demonstrate manifold possibilities and flexibility offered by the LTCC technology to the design of advanced microwave filters on CLCs. Different design and manufacturing aspects are considered. Various design examples of high-performance LTCC resonators and filters for single- and dual-band wireless applications are presented. The designed resonators and filters were manufactured using the commercial DuPont Green Tape 951 LTCC system. The LTCC filters on miniaturized CLCs are shown advantageous with regard to small size, low loss, and absence of spurious response over a wide frequency range.

Single-feed circularly polarized stacked patch antenna with small-frequency ratio for dual-band wireless applications

A single-feed dual-band circularly polarized stacked microstrip patch antenna with a small-frequency ratio is presented. Two pair of orthogonal slits is cut on the lower circular patch for achieving circular polarization and truncated corner square patch is used as the upper parasitic element. The frequency ratio of the dual-band is 1.03. The 3 dB axial ratio bandwidth is 1.3% for the upper band and 1.1% for the lower band. Proposed structure is fabricated on the FR-4 epoxy substrate and fed by SMA connector. The measured results are in good agreement with the theoretical and simulated results. The antenna shows stable radiation characteristics in both bands of operation.

Cantor fractal-based printed slot antenna for dual-band wireless applications

Fractal geometries are attractive for antenna designers seeking antennas with compact size and multiband resonant behavior. This paper presents the design of a new microstrip-fed printed slot antenna for use in dual-band wireless applications. The slot structure of the proposed antenna is in the form of Cantor square fractal geometry of the second iteration. The slot structure has been etched on the ground plane of a substrate with relative permittivity of 4.4 and 1.6 mm in thickness. A parametric study is conducted to explore the effects of some geometrical parameters on the antenna performance. Results show that the antenna possesses a dual-band behavior with a wide range of resonant frequency ratio. In addition to the ease of fabrication and simple design procedure, the antenna offers desirable radiation characteristics. A prototype of the proposed antenna has been simulated, fabricated, and measured. The measured 10 dB return loss bandwidths for the lower and the upper resonant bands are 42% (2.35–3.61 GHz) and 20% (5.15–6.25 GHz), respectively. This makes the proposed antenna suitable to cover a number of operating bands of wireless systems (2.4 GHz-Bluetooth, 2.4 GHz ISM, 2.4/5.8 GHz-WLAN, 3.5 GHz-WiMAX, and 5.8 GHz-ITS).

Complementary Sierpinski gasket fractal antenna for dual-band WiMAX/WLAN (3.5/5.8 GHz) applications

A proximity-fed complementary Sierpinski gasket fractal with equilateral triangular shape resonator in multilayer structure to achieve dual-band behavior for WiMAX and WLAN applications has been proposed. An electromagnetic coupled stacked structure of two different patches operating at two frequencies (3.5 GHz WiMAX and 5.8 GHz wireless LAN) has been designed for dual-band wireless applications. Proposed antenna was simulated using CST Microwave Studio based on the finite integration technique (FIT) with perfect boundary approximation (PBA). Finally, the proposed antenna was fabricated and some performance parameters were measured to validate against simulation results. The design procedures and employed tuning techniques to achieve the desired performance are presented.

Circular Axe-Shaped Patch Antenna for Compact and Dual Band Wireless Applications

A compact circular AXE-shaped patch antenna is presented for miniaturized application. The proposed design is further modified for dual band 2.4/5.5 GHz wireless application. The measured return loss is from 2.38∼2.42 GHz and 5.41∼5.59 GHz suitable for dual band WLAN application. Same design procedure can also be applied for miniaturized applications. The miniaturization process shifts the resonance at 1.71 GHz instead of 2.5 GHz in case of simple circular patch. The radiation pattern and gain for dual band wireless antenna is also measured and presented.