The design of a four-band slot antenna for the global positioning system (GPS), worldwide interoperability for microwave access (WiMAX), and wireless area network (WLAN) is presented. The antenna consists of a rectangular slot with an area of ${\mathbf{0}}.{\mathbf{37}}{\lambda _g} \times {\mathbf{0}}.{\mathbf{14}}{\lambda _g} = {\mathbf{48}} \times {\mathbf{18}}\;{\bf m}{{\bf m}^{\mathbf{2}}}$ (where ${\lambda _g}$ is the guide wavelength), a $T$ -shaped feed patch, an inverted $T$ -shaped stub, and two $E$ -shaped stubs to generate four frequency bands. The radiating portion and total size of the antenna are less than those of the tri-band antennas studied in literature. Parametric study on the parameters for setting the four frequency bands is presented and hence the methodology of using the design for other frequency bands is proposed. The multiband slot antenna is studied and designed using computer simulation. For verification of simulation results, the antenna is fabricated and measured. The simulated and measured return losses, radiation patterns, realized peak gains, and efficiencies of the antenna are presented. Measured results show that the antenna can be designed to cover the frequency bands from 1.575 to 1.665 GHz for the GPS system, 2.4–2.545 GHz for the IEEE 802.11b&g WLAN systems, 3.27–3.97 GHz for the WiMAX system, and 5.17–5.93 GHz for the IEEE 802.11a WLAN system. The effects of the feeding cable used in measurement and of the cover are also investigated.

A Multiband Slot Antenna for GPS/WiMAX/WLAN Systems

We present a 4-port Multiple-Input-Multiple-Output (MIMO) antenna array operating in the mm-wave band for 5G applications. An identical two-element array excited by the feed network based on a T-junction power combiner/divider is introduced in the reported paper. The array elements are rectangular-shaped slotted patch antennas, while the ground plane is made defected with rectangular, circular, and a zigzag-shaped slotted structure to enhance the radiation characteristics of the antenna. To validate the performance, the MIMO structure is fabricated and measured. The simulated and measured results are in good coherence. The proposed structure can operate in a 25.5–29.6 GHz frequency band supporting the impending mm-wave 5G applications. Moreover, the peak gain attained for the operating frequency band is 8.3 dBi. Additionally, to obtain high isolation between antenna elements, the polarization diversity is employed between the adjacent radiators, resulting in a low Envelope Correlation Coefficient (ECC). Other MIMO performance metrics such as the Channel Capacity Loss (CCL), Mean Effective Gain (MEG), and Diversity gain (DG) of the proposed structure are analyzed, and the results indicate the suitability of the design as a potential contender for imminent mm-wave 5G MIMO applications.

4-Port MIMO Antenna with Defected Ground Structure for 5G Millimeter Wave Applications

This paper presents a dual-band planar antenna with a compact radiator for 24/52/58-GHz wireless local area network (WLAN) applications The antenna consists of an L-shaped and -shaped radiating elements to generate two resonant modes for dual-band operation The -element fed directly by a 50-Ω microstrip line is designed to generate a frequency band at around 55 GHz to cover the two higher bands of the WLAN system (using the IEEE 80211a standard) The L-element is coupled-fed through the L-element and designed to generate a frequency band at 244 GHz to cover the lower band of the WLAN system (using the 80211 b/g standards) As a result, the L- and E-elements together are very compact with a total area of only 8 × 113 mm2 Parametric study on the key dimensions is investigated using computer simulation For verification of simulation results, the antenna is fabricated on a 40 × 30 × 08 mm3 substrate and measured The effects of the feeding cable used in the measurement system and the housing and liquid crystal display of wireless devices on the return loss, radiation pattern, gain and efficiency are also investigated by computer simulation and measurement

Dual-Band Antenna With Compact Radiator for 2.4/5.2/5.8 GHz WLAN Applications

The ultrawideband (UWB) planar antenna is designed as a circular metallic patch fed by a coplanar waveguide (CPW). This antenna provides the impedance bandwidth of the wideband response from 2.5 to 12 GHz. To achieve the notched characteristics at desirable frequencies, the electric ring resonator (ERR) incorporated into the CPW feedline is proposed for use in the planar configuration of the UWB antenna. The notched frequency band is controlled by dimensions of the ERR structure. The single-notched band can be obtained by placing a single ERR beneath the CPW structure. For implementation of the multinotch band, a modified multimode structure of the ERR is examined. Reconfigurability of the first notched band is provided by using a digital variable capacitor (DVC) instead of ERR's quasi-lumped capacitance. The results of simulations and measurements are in a good agreement.

Ultrawideband (UWB) Planar Antenna with Single-, Dual-, and Triple-Band Notched Characteristic Based on Electric Ring Resonator

A compact planar ultra-wideband (UWB) antenna with triple band notch characteristics is proposed in this paper. The antenna consist a rectangular radiating patch, a modifled partial ground plane, and has an overall dimension of 30 £ 22mm 2 . Three resonant elements are placed above the ground plane to generate three notch frequency bands separately in the WiMAX, the lower WLAN and the upper WLAN frequency bands. The proposed antennas are successfully simulated, prototyped and measured. Efiects of the key deign parameters on band notch characteristics are also investigated. The realized antenna achieved an operating bandwidth (VSWR • 2) ranges from 2.9 to more than 11GHz with triple notched bands of 3.26{ 3.71 (12.9%), 5.15{5.37 (8.5%), and 5.78{5.95 (2.9%)GHz. Measured ∞at transfer function and constant group delay within the operating band except notched bands make the proposed antenna suitable for being used in practical UWB applications.

/pdf/triple-band-notched-planar-uwb-antenna-using-parasitic-1v718teh0i.pdf

Triple Band-Notched Planar UWB Antenna Using Parasitic Strips

Coaxial cable is often used for measurements of antennas inside anechoic chambers. In the measurement of a monopole antenna with a small ground-plane, the finite-sized ground causes the current to flow back from the radiator to the outer surface of the coaxial cable. This results in secondary radiation which introduces errors to the measured radiation pattern. To reduce the unwanted secondary radiation, the coaxial cable can be covered with EMI suppressant tubing materials. However, this introduces errors to the measured efficiency. In this paper, the models of the coaxial cable with and without suppressant tubing are developed and used for computer simulation. The cable effects on the measured results of a small monopole ultrawide band (UWB) antenna are studied by using the antenna measurement equipment Satimo StarLab and the EM simulation tool CST. The results show great agreements between the simulated and measured results.

Modeling of cable for measurements of small monopole antennas

In this paper, the design of a novel chipless ultra-wideband radio-frequency identification (UWB RFID) system is proposed. The system employs printable uniplanar chipless tags and a pair of high-gain reader antennas. The chipless tag is composed of two UWB monopole antennas, connected by a coplanar waveguide (CPW). The tag's ID is represented by a spectral signature in the UWB frequency range, and is created by a multi-resonator embedded on the coplanar waveguide. The detection of the tag's ID is based on using only the amplitude of the spectral signature, which significantly simplifies the complexity of detection. The reader employs two separate Vivaldi antennas - one for transmitting a vertically polarized signal, and the other for receiving a horizontally polarized signal - to reduce the mutual coupling between the uplink and downlink signals. Further reduction of mutual coupling is achieved by using a copper plate at the reader to separate the uplink and downlink signals. These two proposed methods together reduced the mutual coupling by 20 dB. The chipless RFID tag with eight coplanar waveguide resonators in a group and the reader antennas were designed using computer simulation, and fabricated on Rogers substrates for measurement. The results of studies in an anechoic chamber showed that the proposed UWB RFID system could achieve a reading range of larger than 30 cm, at least three times longer than the maximum distance of a similar system reported by others. This indicated that the proposed system has great potential for short-range item tracking at low cost.

Design of Chipless UWB RFID System Using A CPW Multi-Resonator

In this paper, the design of a UWB antenna using a transparent AgHT-8 material is proposed for green wireless applications. Computer simulation is used for studies. For verification of the design, the proposed antenna is fabricated on an AgHT-8 film and measured. Results show that the antenna has better radiation efficiency relative to its size than the previous designs, good omni-directional radiation patterns throughout the FCC bandwidth of 3.1–10.6 GHz and a comparable gain. To filter out the unwanted signals in the WLAN band, two vertical slots are introduced to produce a tuning notch in the 5 GHz frequency band. For demonstration of green wireless applications, the transparent antenna is incorporated with a solar panel for harnessing solar energy. Results show that the transparency of the antenna makes it a good candidate for future green wireless applications.

/pdf/miniature-transparent-uwb-antenna-with-tunable-notch-for-4aqr58ltyw.pdf

Miniature transparent UWB antenna with tunable notch for green wireless applications

In this paper, three pairs of meandered ground stubs are used to create a triple band-notched characteristic for a compact planar-monopole antenna used in the ultrawide band (UWB). The three band notches include the IEEE 802.16 (WiMax) band (3.3–3.6 GHz), the lower wireless area network (WLAN) band (5.15–5.35 GHz) and the higher WLAN band (5.725–5.825 GHz). The center frequencies and bandwidths of the notches can be adjusted using the dimensions of the meandered ground stubs. Prototype of the proposed antenna is designed and fabricated. The band-notched characteristics, return loss, radiation patterns, peak gains and efficiencies of the antenna are studied using both computer simulation and measurements.

/pdf/triple-band-notched-uwb-antenna-using-meandered-ground-stubs-40cn5tr4wi.pdf

Triple band-notched UWB antenna using meandered ground stubs

The paper proposes to use meandered grounded stubs to design single or dual band-notched planar-monopole antennas for ultrawide band (UWB) applications. The center-notch frequencies and notch bandwidths of the UWB antennas can be adjusted by using the dimensions of the meandered grounded stubs. Two prototype antennas are designed, fabricated and studied. One has a single band notch in the wireless area network (WLAN) band from 5.15 GHz to 5.825 GHz and the other one has two sets of dual-band notches at the lower WLAN band (5.15–5.35 GHz) and higher WLAN band (5.725–5.825 GHz). The band-notched characteristics, radiation patterns and peak gains of the antennas are studied using computer simulation and measurements.

/pdf/uwb-antenna-with-single-or-dual-band-notched-characteristic-3crweuvphy.pdf

T. I. Yuk

Papers

Modeling of cable for measurements of small monopole antennas

Design of Chipless UWB RFID System Using A CPW Multi-Resonator

Miniature transparent UWB antenna with tunable notch for green wireless applications

Triple band-notched UWB antenna using meandered ground stubs

UWB antenna with single or dual band-notched characteristic for WLAN band using meandered ground stubs