T-shaped Strip Research Articles

Compact Design of an UWB Antenna with Dual Band-Notched Characteristic

An ultra-wideband (UWB) printed antenna with dual band-notched characteristic is presented in this paper. The proposed antenna is composed of a semi-circular patch fed by a tapered coplanar waveguide (CPW) and an unclosed ground plane, which are printed onto the same side of a FR4 printed circuit board (PCB) with an overall size of 30 mm × 30 mm × 1.5 mm. By embedding a simple arc-shaped slot in the patch and adding a T-shaped strip on the top of the patch, two notched frequency bands for rejection of WiMAX and WLAN system can be realized. The characteristics of the proposed antenna are investigated by using the software HFSS and validated experimentally, both simulated and measured results show that the proposed antenna prototype achieves good impedance matching over an frequency band from 2.1011.40 GHz for VSWR2 with two notched bands over the frequency range of 5-5.95 GHz and 3.1-3.9 GHz. Furthermore, a relatively stable gain and suitable radiation patterns are also achieved in both lower and upper UWB frequency band.

Design and Optimization of Integrated Bluetooth and UWB Antenna With Dual Band-Notched Functions

A compact microstrip-fed printed planar integrated Bluetooth and ultra wideband (UWB) monopole antenna with dual band-notched characteristics in the 3.5 GHz WiMAX and 5.2/5.8GHz WLAN band is presented. The proposed antenna design consists of the semicircular ring patch and partial ground plane. The extra band (2.33-2.5GHz)for Bluetooth is obtained by adding the T-shaped strip at the top of the patch. Additionally, two L-shaped arc slots in patch and two U-shaped circular slots in partial ground plane are etched to reject the WiMAX and WLAN bands. The numerical and experimental results show that the proposed antenna has an impedance bandwidth of VSWR ≤ 2 from 2.33 GHz to 2.5 GHz for Bluetooth band and 3.04 GHz to 10.8 GHz for UWB band except the notch band frequencies 3.34.1 GHz for WiMAX and 5 – 5.9 GHz for WLAN band.

Small square slot antenna with dual band-notch function by using inverted T-shaped ring conductor-backed plane

In this article, a novel method for designing a new slot antenna with dual band-notch characteristic for ultra-wideband applications has been presented. By inserting a coupled inverted T-shaped ring strip on the other side of the substrate, a dual band-notch function generated, also additional resonance is excited and hence much wider impedance bandwidth can be produced, especially at the higher band. The measured results reveal that the presented dual band-notch slot antenna offers a 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 20 × 20 mm2. Good return loss and radiation pattern characteristics are obtained in the frequency band of interest. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2267–2270, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27057

Circularly Polarized Square Slot Antenna With a Largely Enhanced Axial-Ratio Bandwidth

A new easy-to-apply design procedure is proposed in this letter for constructing small wideband circularly polarized (CP) bidirectional and unidirectional square slot antennas. With an asymmetric T-shaped strip protruded from the signal line of the feeding coplanar waveguide (CPW) into the square slot, a reference antenna with a fractional 3-dB axial-ratio bandwidth (abbreviated as CPBW) of about 11% can be obtained. The proposed bidirectional CP slot antenna (BICPSA) can be modified from the reference antenna by stretching the left end of the T-shaped strip upward, by embedding a rectangular metal patch in the square slot, and by implanting a grounded metal strip from the right edge of the slot. The resulting BICPSA has a much larger CPBW of 39.1%, which is about 3.55 times that of the reference antenna. Finally, by placing a simple reflector underneath this BICPSA without changing its structural dimensions, one can obtain unidirectional radiation patterns with a greatly increased gain of 7.6 dBic, but with only a slightly decreased CPBW of 34.3%.

A COMPACT CPW-FED OMNI-DIRECTIONAL MONOPOLE ANTENNA FOR WLAN AND RFID APPLICATIONS

A compact dual-band CPW-fed triangle-shaped antenna is proposed for applications in 2.4/5GHz WLAN and RFID. The designed antenna, including ground plane, is only 28mm in height and 26mm in width. By introducing a ƒ-shaped slot and a T-shaped strip, the proposed antenna can generate two separate impedance bandwidths. Prototypes of the proposed antenna have been constructed and tested. The measured impedance bandwidths, ranging from 2.36GHz to 2.50GHz and from 5.01GHz to 6.33GHz separately, are obtained with return loss less than i10:00dB, which meet the required bandwidths speciflcation of WLAN and RFID. Good omni- directional radiation and appropriate gain characteristics in the desired frequency bands have been achieved.

UWB Omnidirectional Square Monopole Antenna for Use in Circular Cylindrical Microwave Imaging Systems

In this letter, a novel ultrawideband (UWB) printed monopole antenna (PMA) for use in a circular cylindrical microwave imaging system is presented. The proposed antenna consists of a square radiating patch and a ground plane with a pair of E-shaped slots and a rectangular slot with a pair of horizontal T-shaped strips protruded inside the slot, which provides a wide usable fractional bandwidth of more than 120% (2.97-12.83 GHz). By cutting two modified E-shaped slots with variable dimensions on the ground plane corners and also by inserting two T-shaped strips inside the rectangular slot located in the ground plane center, additional resonances are excited, and hence much wider impedance bandwidth can be produced, especially at the higher band. The proposed antenna has an ordinary square radiating patch, therefore displays a good omnidirectional radiation pattern even at higher frequencies, and also its radiation efficiency is greater than 86% across the entire radiating band. The designed antenna has a small size of 12 ×18 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Simulated and measured results are presented to validate the usefulness of the proposed antenna structure for circular cylindrical microwave imaging system.

Compact wide tri-band slot antenna for WLAN/WiMAX applications

A compact wide tri-band microstrip-fed slot antenna for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) application is presented. Three operating bands are achieved by inserting a pair of T-shaped strips into a wide rectangular slot. The bandwidth enhancement is obtained by introducing a staircase pattern into the wide rectangular slot. A fabricated prototype for the proposed tri-band antenna has compact dimensions of 36×30×mm 2 , and provides a wide impedance bandwidth. The measured impedance bandwidth for 10dB return loss at 2.5, 3.5, and 5.6 GHz operating band can be up to 540, 940, and 950 MHz, respectively. Moreover, the antenna shows monopole-like radiation patterns and stable antenna gains across the three operating bands.

Design of compact planar ultrawideband antenna with dual-notched bands using slotted square patch and pi-shaped conductor-backed plane

A planar antenna with ultrawideband (UWB) performance and dual band-notched characteristics is proposed. The main features of the antenna are the compact dimensions and omnidirectional radiation across the whole band of operation. The radiator of the antenna is a slotted square patch. The ground plane is located at the bottom layer, which also includes a Π-shaped conductor-backed plane used to widen the impedance bandwidth. Dual band-notched characteristics are achieved by an inverted T-shaped strip inside the slotted radiator and a pair of mirror inverted L-shaped slots at the two sides of the radiator. The measured results of the manufactured (12 × 16 mm) antenna on 1.6 mm FR4 substrate show that the antenna operates with voltage standing wave ratio (VSWR) less than two over the frequency band from 2.5 to 10.8 GHz. That wideband is featured by the existence of two notched bands (3.23-4.3 and 5-6 GHz), where the VSWR is more than nine, aimed at suppressing any interference from IEEE802.16 WiMAX (3.3-3.6 GHz), C-band systems (3.7-4.2 GHz) and IEEE802.11a WLAN (5.15-5.825 GHz). The antenna has an omnidirectional radiation across the whole UWB as validated by the measured radiation pattern and gain.

Planar multiband antenna for multistandard mobile handset applications

A planar antenna for multiband operation is presented. The proposed microstrip-fed antenna includes a slotted ground plane, a T-shaped radiator, meandered and open circuit strips. A return loss of better than 10 dB is achieved at the frequency bands personal communication system (PCS) (1850-1990 MHz), UMTS (1920-2170 MHz), WiBro (2300-2390 MHz), WLAN + Bluetooth (2400-2480 MHz), WiMAX (2500-2690 MHz), and WiMAX (3400-3600 MHz). If a return loss of 6 dB is considered as a standard, the antenna can cover DCS (1710-1880 MHz). The proposed antenna occupies a small volume of 40 x 30 x 1.6 mm(3), which makes it attractive to the portable devices. The simulated and measured performance of the antenna confirms its multiband operation and omnidirectional radiation pattern. (C) 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2700-2703, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26319

Broadband planar antenna with T-shaped strip and capacitively coupled shorted strip

This letter describes a broadband planar antenna embedded in LTE700/GSM handheld terminals. The antenna consists of a T-shaped strip fed by a 50-Ω coaxial cable and a shorted strip excited by capacitive coupling. The capacitively coupled shorted strip shows the resonance at the lower frequency band, and the T-shaped strip presents good matching at the higher frequency band, because the characteristics of input impedance are affected by the capacitive coupling. The proposed antenna was simulated and fabricated. The measured bandwidth based on 3:1 VSWR was 0.62–1.53 GHz, which covers the frequencies used for LTE700, GSM800/850/900 mobile communications as well as the military applications. This antenna would be also useful for broadband wireless communications using the technique such as software-defined radio or cognitive radio. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26211

Band-Notched Small Square-Ring Antenna With a Pair of T-Shaped Strips Protruded Inside the Square Ring for UWB Applications

A novel printed monopole antenna with constant gain over a wide bandwidth for ultra wideband applications with desired notch-band characteristic is presented. The proposed antenna consists of a square-ring radiating patch with a pair of T-shaped strips protruded inside the square ring and a coupled T-shaped strip and a ground plane with a protruded strip, which provides a wide us able fractional bandwidth of more than 130% (3.07-14.6 GHz). By using the square-ring radiating patch with a pair of T-shaped strips protruded inside it, the frequency bandstop performance is generated, and we can control its characteristics such as band-notch frequency and its bandwidth by electromagnetically adjusting coupling between a pair of T-shaped strips protruded inside the square ring. The designed antenna has a small size of 12 × 18 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , or about 0.15λ × 0.25λ at 4.2 GHz, while showing the band-rejection performance in the frequency band of 5.05-5.95 GHz.

Dual-Band Dual-Sense Circularly-Polarized CPW-Fed Slot Antenna With Two Spiral Slots Loaded

A novel design of a dual-band dual-sense circularly-polarized CPW-fed slot antenna with two spiral slots loaded is presented. The two loaded spiral slots in the ground plane can result in different senses of circular polarization. The dual-band operation is achieved by using the T-shape strip. The ratio of two frequencies is 1.375. The antenna is designed, fabricated, and measured. It is shown that the proposed antenna has good circular polarization characteristic. The measured 10 dB return loss impedance bandwidths are 8.7% for the lower band (RHCP) and 23% for the upper band (LHCP). The measured 3 dB axial-ratio bandwidths are 8.4% and 19.24%, with respect to 1.6 GHz (RHCP) and 2.2 GHz (LHCP), respectively.

A Novel Patch Antenna with a T-shaped Parasitic Strip for 2.4/5.8 GHz WLAN Applications

A novel dual-band design of patch antenna is presented in this paper. Using a T-shaped parasitic strip, the patch antenna is able to generate two separate resonant modes to cover 2.4/5.8 GHz (wireless local area network) WLAN bands with satisfactory radiation properties. The impedance bandwidth of the proposed antenna is 250MHz centered at 2.42 GHz and 750MHz centered at 5.78 GHz for S11 < −10dB. The parameters which affect the performance of the antenna in terms of its frequency domain characteristics are investigated.

Internal monopole antenna integrated with a shielding metal case for UMTS mobile devices

An integration design of an internal monopole antenna and an RF shielding metal case for application in UMTS mobile devices is proposed. The monopole antenna is a low-profile (only 3.5-mm) T-shape strip monopole placed above and integrated (through short-circuiting) to the shielding metal case, which is flush with the top edge of the system ground plane of the mobile device. With the integrated shielding case, which provides a coupling-free region for the nearby components such as the RF module, RF circuitry, and battery in the mobile device, possible coupling between the monopole antenna and the nearby components can be avoided. The proposed integration design can thus lead to no degrading effects on the performances of the internal monopole antenna employed in the mobile device. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 162–165, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21293

Design and analysis of a combination antenna with rectangular dielectric resonator and inverted L-plate

A wide-band compact antenna combining a rectangular dielectric resonator (DR) with a grounded and inverted L-plate is proposed. Two different impedance matching circuits, a vertical T-shaped strip attached to one side of the DR and a microstrip stub terminated into a T-branch, are introduced to enhance the impedance matching and to economize the space utilization by the matching circuits. A two-step procedure is applied to design the radiation element and the feed structure of the antenna. Approximate formulas are used to obtain initial estimation of the antenna dimensions. Then finite-difference time-domain method (FDTD) with the help of fast Fourier transform/Pade/spl acute/ method is used for fine-tuning these dimensions to obtain satisfactory resonant frequency and quality factor. Next, the feed structure is designed and adjusted to obtain the optimal impedance matching. Since the radiation element and the feed structure are designed separately, the design process is simplified and both their performances are optimized within the frame of design restrictions. Two antennas, for 2.4 and 5.8 GHz Bluetooth and wireless local-area network applications, are designed as examples. The -10 dB bandwidths between 210 and 240 MHz are obtained. The antenna gains are 1.0 and 1.5 dBi, respectively.

Coplanar waveguide-fed square slot antenna for broadband circularly polarized radiation

A new design of a broadband circularly polarized square slot antenna fed by a single coplanar waveguide (CPW) is proposed and experimentally studied. The proposed broadband circular polarization (CP) operation is achieved by protruding a T-shaped metallic strip from the ground plane toward the slot center and feeding the square slot antenna using a 50-/spl Omega/ CPW with a protruded signal strip at 90/spl deg/ to the T-shaped strip. Experimental results of constructed prototypes show that the obtained 3-dB and 1-dB axial-ratio bandwidths can reach as large as 18% and 13%, respectively. The proposed antenna also has a peak antenna gain of about 4 dBi, with gain variations less than 1 dBi for frequencies within the CP bandwidth.