In this study, a novel method for designing a new monopole antenna with dual band-notched characteristic for UWB applications has been presented. The proposed antenna consists of a square radiating patch with a modified T-shaped slot, and a ground plane with two E-shaped slots and a W-shaped conductor backed-plane. By cutting two E-shaped slots in the ground plane, additional resonance is excited and hence much wider impedance bandwidth can be produced, especially at the higher band, which results in a wide usable fractional bandwidth of more than 130% (2.73%13.3 GHz). In order to generate single band-notched characteristic, the authors use a W-shaped conductor backed-plane structure on the other side of the substrate. In addition, by cutting a modified T-shaped slot in the radiating patch and microstrip feed-line, a dual band-notched function is achieved. The measured results reveal that the presented dual notch band monopole antenna offers a very wide bandwidth with two notched bands, covering all the 5.2/5.8 GHz wireless local area network, 3.5/5.5 GHz WiMAX and 4 GHz C bands. The designed antenna has a small size of 12 % 18 mm 2 . Good voltage standing wave ratio (VSWR) and radiation pattern characteristics are obtained in the frequency band of interest. Simulated and measured results are presented to validate the usefulness of the proposed antenna structure for ultra-wideband (UWB) applications.

Dual band-notched small monopole antenna with novel W-shaped conductor backed-plane and novel T-shaped slot for UWB applications

In this paper, a compact monopole wideband antenna is designed and manufactured for ultra-wide band (UWB) applications. In order to extend the impedance bandwidth of the proposed antenna, rectangular and triangular slots are etched from the partial ground and from the center of the rectangular patch respectively. Also, by cutting the lower corners of the radiating patch using stepped technique, additional resonances are regenerated and lead to further improvement in the covered bandwidth. The proposed patch antenna has advantageous of compactness its overall size equals 40 × 40 mm2.Simulated and measured results show that the proposed antenna design exhibits a bandwidth from 2.9 – 19.2 GHz for VSWR< 2. The antenna structure provides a wide usable fractional bandwidth of 148%. These inherent characteristics of the proposed antenna make it suitable for efficient transmission and reception in UWB systems. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1514–1519, 2016

A novel compact UWB monopole antenna with enhanced bandwidth using triangular defected microstrip structure and stepped cut technique

In this paper, a difierent method for designing a novel and compact microstrip-fed slot antenna with band-notched characteristic for UWB application is proposed. In the proposed antenna, a pair of cross-shaped strips protruded inside an extra rectangular slot in the ground plane are used to crate an additional resonance in higher frequencies. By obtaining this resonance, the usable upper frequency of the antenna is extended from 9 to 14.8GHz which provides a wide usable fractional bandwidth of more than 135%. Additionally, by using a square ring radiating stub with a pair of protruded T-shaped strips inside the ring, a desired frequency band-stop performance has been obtained. Good antenna gain and VSWR characteristics are obtained in the frequency band of interest. The proposed antenna can operate from 3.04 to 14.8GHz for VSWR < 2 with a rejection band around 5.1 to 6GHz to suppress any interference from wireless local area network (WLAN) systems. Simulated and experimental results obtained for this antenna show that it exhibits good radiation behavior within the UWB frequency range.

/pdf/application-of-protruded-strip-resonators-to-design-an-uwb-3gqyetilyx.pdf

Application of Protruded Strip Resonators to Design an UWB Slot Antenna with WLAN Band-Notched Characteristic

Ultra-wideband (UWB) antennas are gaining prominence and becoming very attractive in modern and future wireless communication systems, mainly due to two factors. Firstly, people increasingly high demand for the wireless transmission rate and UWB properties such as high data rate, low power consumption and low cost, which give a huge boost to the UWB antennas’ research and development in industry and academia since the Federal Communications Commission (FCC) officially released the regulation for UWB technology in 2002. Secondly, now the wireless portable device need antenna operated in different frequencies for various wireless transmission functions, and operation bands and functions are increasing more and more, which may result in challenges in antenna design, such as antenna space limitation, multi antennas interference, and etc. One UWB antenna can be used to replace multi narrow-band antennas, which may effectively reduce the antenna number.

/pdf/ultra-wideband-antenna-and-design-4fxqd8zo4g.pdf

Ultra-Wideband Antenna and Design

A new design of a multi-resonance small slot antenna with variable band-notched function for ultra-wideband (UWB) applications is proposed. The proposed slot antenna consists of a square radiating stub and a ground plane with a pair of L-shaped parasitic structures and an inverted T-shaped strip protruding inside the rectangular slit, which provides a wide usable fractional bandwidth of more than 135% (2.98–16.73 GHz), while showing the band rejection performance in the frequency band of 5.05–5.9 GHz to avoid any interference from wireless local area network systems. The designed antenna has a small size of 20 × 20 × 0.8 mm3. Simulated and experimental results obtained for this antenna show that it exhibits good radiation behaviour within the UWB frequency range.

UWB small slot antenna with WLAN frequency band-stop function

This is a presentation of a compact wide-slot antenna with microstrip-fed monopole for ultrawideband (UWB) application. The monopole is composed of an elliptic patch connected to a trapezoid one. The radiator patch is attached to a 50-Ω microstrip feed line by a smoothly tapered line to enhance the wideband matching. A hexagonal slot is etched from a finite ground plane placed on the other side of the substrate. The antenna has compact physical structure and is designed on standard FR4 substrate. Simulation and optimization with Ansoft HFSS and CST Microwave Studio software indicate 145% fractional impedance bandwidth varying from 2.9 to 18 GHz for VSWR less than 2. The antenna is successfully fabricated and characterized by measuring VSWR, radiation pattern, and gain. Comparison between simulated and experimental results exhibits a near agreement in the operating band. In addition, it yields an average gain of several decibels with low tolerance and reasonable stable radiation characteristics. The effects of vital parameters on antenna performance and some other details are analyzed and discussed as well.

A Compact Hexagonal Wide-Slot Antenna With Microstrip-Fed Monopole for UWB Application

In this paper, a conical horn antenna in the presence of a metamaterial lens in the X-band is introduced and fabricated. The annular metamaterial lens is located at the aperture of a shortened horn antenna, whose length is half the length of the corresponding optimum horn. The phase velocity in the metamaterial lens is more than the phase velocity along the axis of the antenna for the same propagation distance, so the phase distribution at the aperture of the antenna is uniform and the gain of the shortened horn antenna increases. Metamaterial cells are designed in the form of a printed circuit board that have easy to build and suitable cost. The design process is based on how the waves incident on the proposed metamaterial cell, and finally, by using the particle swarm optimisation (PSO) algorithm proper radiation characteristics in the desired frequency range can be achieved. The radiation characteristics of an antenna with a metamaterial lens are similar to that of an antenna with optimum length in the desired frequency band. The difference is that the weight and volume of these antennas are reduced, so they have better performance in satellite and radar systems. 

Size reduction of a conical horn antenna loaded by multi‐layer metamaterial lens

We have proposed a dispersive formulation of scalar-based meshless method for time-domain analysis of electromagnetic wave propagation through left-handed materials (LHMs). Moreover, we have incorporated Berenger’s perfectly matched layer (PML) absorbing boundary condition (ABC) into the dispersive formulation to truncate open-domain structures. In general, the dispersive formulations of conventional numerical methods are proper tools for analysis of left-handed (LH) media, whenever the LH media can be characterized by considering spatial or frequency dispersion effect for the constitutive parameters. In comparison to the grid-based numerical methods, it is proven that meshless methods not only are strong tools for accurate approximation of derivatives in Maxwell’s equations but also can provide more flexibility in modeling the spatial domain of problems. However, we have not seen any reports on using dispersive forms of meshless methods for simulation of wave propagation in metamaterials and applying any PML ABCs to dispersive formulation of meshless method. The proposed formulation enables us to take advantage of meshless methods in analysis of LH media with frequency-dependent parameters. For modeling the frequency behavior of the medium, we have used auxiliary differential equation (ADE) method based on the relations between electromagnetic fields intensities and current densities. Effectiveness of the proposed formulation is verified by analysis of 2-D and 3-D numerical examples; also, some basic factors which affect the accuracy, stability, and computational cost of the simulations are studied.

A Dispersive Formulation of Time-Domain Meshless Method With PML Absorbing Boundary Condition for Analysis of Left-Handed Materials

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1049/mia2.12240

H‐plane horn antenna with very low side lobes using partially dielectric‐filled gap waveguide technology

In this paper, the Electromagnetic Band-Gap (EBG) structures have been used to decrease the mutual coupling between two wideband quad-ridge horn antennas. The EBG structure is a small sheet with a length of 6 cm and a width of 10.6 cm, and it was placed vertically between the horn antennas, providing us with a very compact system. Full-wave CST simulations have been carried out to simulate the whole structure. A two-layer EBG structure has provided a 17 dB isolation over the 20-40 GHz frequency range. Moreover, to verify the proposed structure, EBG layers have been fabricated and measured. The S parameter and far-field measurements of the horn antennas were conducted to investigate the isolation and radiation patterns of the antennas. The measurement results were perfectly comparable with the simulations. Moreover, because of the standalone characteristic of the designed EBGs, this structure can be used as an add-on unit to decrease the E-plane mutual coupling of any two antennas. 

F. Mohajeri

Papers

A Compact Hexagonal Wide-Slot Antenna With Microstrip-Fed Monopole for UWB Application

Size reduction of a conical horn antenna loaded by multi‐layer metamaterial lens

A Dispersive Formulation of Time-Domain Meshless Method With PML Absorbing Boundary Condition for Analysis of Left-Handed Materials

H‐plane horn antenna with very low side lobes using partially dielectric‐filled gap waveguide technology

Coupling Reduction of Two Adjacent Quad-Ridge Horn Antennas at 20-40 GHz Frequency Range by Using of Wideband Electromagnetic Band Gap Structure