This paper presents the design of a compact split ring resonator (SRR) loaded coplanar waveguide (CPW) fed ultrawideband circular monopole antenna having frequency notch characteristics. The electromagnetic coupling of the SRR with the CPW yields the frequency notch. Fabricated prototypes were measured and compared with simulations and good agreement was obtained. The impedance and radiation plots confirm the suppression of the desired notch frequency. A theoretical formulation to calculate the notch frequency is also proposed and validated.

Compact SRR loaded UWB circular monopole antenna with frequency notch characteristics

A new approach is proposed to reject certain bands within the passband of an ultra-wideband planar monopole antenna. The proposed approach that utilizes a mushroom-type electromagnetic-bandgap (EBG) structure is proven to be an effective way for band-notched designs. The approach has many advantages, such as notch-frequency tunability, notch-band width controllable capacity, efficient dual-notch design, and stable radiation patterns. Several design examples using conventional mushroom-type EBG and edge-located vias mushroom-type EBG are presented. The examples exhibit good bandstop characteristics to reject the wireless local-area network interference bands (5.2- and 5.8-GHz bands). Besides, the causes that lead to the discrepancies between the simulations and measurements are discussed.

UWB Band-Notched Monopole Antenna Design Using Electromagnetic-Bandgap Structures

A new technique to achieve both good isolation and dual band-notched functions for ultrawideband (UWB) multiple-input–multiple-output (MIMO) antennas was developed. The proposed antenna consists of the radiation patch connected through a via with the strip placed beneath the patch. The strip not only provides another coupling path, but also serves as the impedance transformer, resulting in good isolation ( $S_{21} dB) and dual band rejection at WiMAX (3.4–3.7 GHz) and WLAN (5.15–5.35 and 5.725–5.825 GHz) over the UWB system operation (3.1–10.6 GHz). Without decoupling element or resonator, which is often placed between the antennas to acquire good isolation or band rejection, the proposed UWB MIMO antenna requires an individual antenna element size of only 11.2 $\,\times\,$ 12 mm $^{2}\ (0.12 \lambda_{0}\times 0.11 \lambda_{0})$ and overall MIMO antenna size of 30 $\,\times\,$ 40 mm $^{2}\ (0.31 \lambda_{0}\times 0.41\lambda_{0})$ . The edge-to-edge separation between antennas is $0.052\lambda_{0}$ , and separation between feeds is $0.175 \lambda_{0}$ at 3.1 GHz. Detailed investigations of the parameters were performed, and the experimental results agree closely with the simulation results, demonstrating the feasibility of the proposed method.

An Ultrawideband MIMO Antenna With Dual Band-Notched Function

To mitigate potential interferences with coexisting wireless systems operating over 3.3-3.6 GHz, 5.15-5.35 GHz, or 5.725-5.825 GHz bands, four novel band-notched antennas suitable for ultra-wideband (UWB) applications are proposed. These include UWB antennas with a single wide notched band, a single narrow notched band, dual notched bands, and triple notched bands. Each antenna comprises a half-circle shaped patch with an open rectangular slot and a half-circle shaped ground plane. Good band-notched performance is achieved by using high permittivity and low dielectric loss substrate, and inserting quarter-wavelength horizontal/vertical stubs or alternatively embedding quarter-wavelength open-ended slots within the feed line. The results of both simulation and measurement confirm that the gain suppression of the single and multiple band-notched antennas in each desired notched band are over 15 dB and 10 dB , respectively. The radiation pattern of the proposed triple band-notched design is relatively stable across the operating frequency band.

Multiple Band-Notched UWB Antenna With Band-Rejected Elements Integrated in the Feed Line

An ultra-wideband (UWB) U type monopole antenna fed by a coplanar waveguide (CPW) is proposed. It has low profile and very compact size (14.48 mm × 28.74 mm × 0.8 mm). It provides an wide impedance bandwidth ranging from 3.08 GHz to about 12.75 GHz adjustable by variation of its parameters, such as the relative permittivity and thickness of the substrate, width, and feed and ground plane dimensions. Parametric study is presented. Details of the proposed ultra-wideband design are described. Simulation results are presented and discussed in this paper.

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A planar u type monopole antenna for uwb applications

Anovel ultra-wideband bow-tie slot antenna fed by CPW is proposed in this paper. This antenna has been demonstrated to provide an UWB with return loss less than −10 dB from 9.5 GHz to 22.4 GHz. The bandwidth is up to 80%, which is quite better than the traditional bow-tie slot antenna. Simulated and measured results are presented.

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A novel ultra-wideband bow-tie slot antenna in wireless communication systems

Novel designs for compact dual/triple-band microstrip antennas are proposed with an asymmetric M-shaped patch. The designs utilize vias on the longer arm of the patch for the purposes of compactness and separating of the operational bands. As the two resonant frequencies of antenna 1 are related to certain parts of the patch, one resonant frequency can be flexibly tuned with little effect on the other. A prototype of antenna 1 operating at 2.44 and 5.77 GHz is fabricated and measured. It has a low profile of 0.016 λr1, where λr1 is the wavelength of the first resonant frequency fr1 = 2.44 GHz at free space, and a compact patch size of 0.195 λr1 × 0.177 λr1. The antenna also presents low cross polarization and symmetrical patterns in both E- and H-planes. Finally, a triple-band antenna (antenna 2) with enhanced bandwidth is designed.

Design and Operation of Dual/Triple-Band Asymmetric M-Shaped Microstrip Patch Antennas

A novel compact Archimedean spiral antenna with gap- loading is investigated in this paper. A circular frame sharing the same centre with the spiral elements introduces a capacitive gap. By adjusting the width of the gap and the width of the circular frame, the initial resonant frequency of the proposed antenna is shifted from 2.79 to 1.93 GHz. Compared with the traditional Archimedean spiral antenna with the same lowest operation frequency, the area of the proposed antenna can be reduced by more than 30simulated radiation pattern results.

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Cheng-Li Ruan

Papers

UWB Band-Notched Monopole Antenna Design Using Electromagnetic-Bandgap Structures

A planar u type monopole antenna for uwb applications

A novel ultra-wideband bow-tie slot antenna in wireless communication systems

Design and Operation of Dual/Triple-Band Asymmetric M-Shaped Microstrip Patch Antennas

A Novel Compact Archimedean Spiral Antenna with Gap-Loading