Low profile single feed monopole antenna for quad-band circularly polarised applications

ABSTRACT

A single fed monopole antenna for circularly polarised quad-band applications is presented. The antenna radiator is comprised of half ring-shaped arcs integrated with the 50Ω microstrip feed line. In the proposed design, the circular polarisation is achieved by means of integrating ring, stubs and implanting an open-ended C-shaped slot in the ground surface. The designed antenna has a ?10 dB impedance bandwidth in the range of 2.41 GHz to 4.14 GHz and 4.34 GHz to 6.33 GHz. The 3-dB axial ratio bandwidth varies from 3.01 to 3.21 GHz, 3.46 to 3.79 GHz, 4.53 to 4.68 GHz and 5.08 to 5.10 GHz, therefore, exciting four circularly polarised bands. The proposed antenna covers almost all the IEEE 802.11 and IEEE 802.16 standards and may be a suitable candidate for WLAN and WiMAX applications. The optimisation of the designed antenna is conducted using tool Ansys HFSS and found simulated results in a good match with measured results.     

Dual broadband design of rectangular slot antenna for 2.4 and 5 GHz wireless communication

A novel dual broadband rectangular slot antenna for 2.4 and 5 GHz wireless local area network (WLAN) is proposed. With the use of a U-shaped strip inset at the centre of the rectangular slot antenna, the obtained impedance bandwidths for two operating bands can reach about 10.6% for the 2.4 GHz band and 33.8% for the 5 GHz band, which cover the required bandwidths of IEEE 802.11b/g (2.4-2.484 GHz) and IEEE 802.11a (5.150-5.950 GHz). Details of the antenna design and experimental results are presented and discussed.     

CPW feed circularly polarised microstrip antenna using asymmetric coupling slot

Design of a coplanar waveguide (CPW) feed square microstrip antenna with circular polarisation (CP) radiation is described. This CP design is achieved by using an asymmetric inductively coupling slot in the ground plane of the CPW feed line. Results show that the proposed antenna can have a CP bandwidth of 2.4%, whereas a simple inclined coupling slot case has 1.6% CP bandwidth at a fixed square patch size. Typical experimental results are presented and discussed     

CPW-fed circular slot antenna with slit back-patch for 2.4/5 GHz dual-band operation

A circular slot antenna fed by a coplanar waveguide (CPW) is proposed for dual-band operations. Dual frequency bands that cover the 2.4 GHz (2400-2484 MHz) and 5 GHz (5150-5825 MHz) bands were obtained by embedding a pair of slits in the circular back-patch that is printed on the backside of the substrate and concentric with the circular slot. This design resulted in broadside far-field patterns with low cross-polarisation levels in both frequency bands and a small antenna size of 40/spl times/40 mm with the ground plane regarded as part of the antenna structure.     

Compact circularly polarised microstrip antenna with slotted groundplane

A novel compact circularly polarised microstrip antenna with a slotted ground plane is proposed. By embedding a group of four bent slots in the ground plane and truncating a pair of patch comers in the radiating square patch, the proposed antenna can perform circular polarisation (CP) operation with a reduced antenna size at a fixed operating frequency. In addition, enhanced CP bandwidth and antenna gain for the proposed design are observed. Details of the antenna design and experimental results are presented and discussed     

Ultra-Wideband and Uni-Directional Radiation Slot Antenna for Multi-Band Wireless Communication Applications

In this paper, a ultra-wideband slot antenna is proposed and developed for multi-band wireless communication applications. The radiating slot is fed by a microstrip line with a microstrip fork shaped tuning stub and backed by a finite metallic reflector. The frequency characteristic and radiation performance of the proposed antenna are successfully optimized and the related prototypes are fabricated and tested. The measured results show that the impedance bandwidth can cover the band from 1.85 to 6.1 GHz with return loss of better than 10 dB. The obtained patterns display a high gain and uni-directional radiation patterns within interested bands. With these features, the proposed structure is suitable for application in wireless communication systems, where a single antenna is needed to operate at multi-bands simultaneously, such as PCS (1.85–1.99 GHz), UMTS (1.92–2.17 GHz) and all WLAN bands (2.4–2.48 GHz, and IEEE802.11a WLAN applications: 5.15–5.35 and 5.725–5.825 GHz).     

Implementation and investigation of U-shaped aperture UWB antenna with dual band-notched characteristics

The design and analysis of an ultra-wideband (UWB) aperture antenna with dual band-notched characteristics are presented. The antenna consists of a circular exciting stub on the front side and a U-shaped aperture on the back ground plane. By inserting a slot and a parasitic strip to the antenna, dual notched frequency bands are achieved. A conceptual circuit model, which is based on the measured impedance of the proposed antenna, is also shown to investigate the dual band-notched characteristics. The measured impedance bandwidth defined by VSWR , 2 of 9.0 GHz (2.2?11.2 GHz), with the dual bands of 3.25?4.25 and 5.0?6.05 GHz notched, is obtained.     

Compact annular-ring embedded circular patch antenna with cross-slot ground plane for circular polarisation

A compact circular patch antenna embedded in a narrow annular-ring which uses an unequal cross-slotted ground plane is presented. This new compact structure provides circular polarisation and is easily matched to 50 /spl Omega/ at the low frequency of operation. The size of the proposed antenna is reduced by over 55% compared to the conventional annular-ring CP patch antenna with a strip. The bandwidth and centre-frequency show weak dependence on the position of the feedpoint in the patch and demonstrate wider manufacturing tolerances. Good circularly polarised properties and wide bandwidth are obtained for the proposed compact antenna.     

Slot-coupled microstrip antenna for broadband circular polarisation

A microstrip antenna with broadband circular polarisation (CP) is presented. The proposed microstrip antenna has a circular patch and is excited by a series microstrip-line-feed configuration through the coupling of a ring slot in the ground plane. The broadband operation is achieved by coupling two CP resonant elements, which are due to the circular patch and the ring slot, respectively. A typical prototype using foam material of thickness 5 mm as the antenna substrate is constructed. Measured results show the 3 dB-axial-ratio bandwidth centred at 2500 MHz is more than 10%.     

Compact CPW-fed dual-band antenna

A novel coplanar waveguide (CPW) antenna is proposed for dual-band WLAN applications. It comprises a rectangular patch, a rectangular notch cut at the lower edge of the patch and a CPW transmission line. The rectangular patch together with the ground plane of the coplanar waveguide radiates at the lower frequency band, 2.4 GHz for IEEE 802.11b/g, while the rectangular notch resonates in the upper band, 5.2/5.8 GHz for IEEE 802.11a. The designed antenna is only 32 × 5 mm, which can provide stable omnidirectional radiation patterns with an average gain of 2 dBi in both the bands. The antenna is very compact and suitable for 2.4 and 5.2/5.8 GHz WLAN operations.     

一种面向无线通信应用的宽频带圆极化天线阵

提出了一种新型宽频带2×2方形缝隙槽圆极化天线阵.天线阵包含一个连续旋转馈电结构、4个非对称U型馈电枝节和一个方形槽接地板.与传统圆极化天线阵所采用的L型馈电枝节不同,首次提出了一种新型非对称U形馈电枝节来改善天线的圆极化性能.利用这些枝节和缝隙槽作为微扰元素,缝隙槽天线阵可以激发多重圆极化谐振模式,进而产生宽频带的圆...     

用于WLAN的双频天线的设计与实现

提出了一种应用于无线局域网（WLAN）的新型双频天线。该天线采用微带线馈电的方法,其辐射面呈阶梯形,接地面为＂工＂型宽缝结构,可以覆盖IEEE802.11a/b/g（2.4～2.484GHz,5.15～5.825GHz）频段标准。其回波损耗小于10dB的阻抗带宽在2.4GHz频段可达160MHz（2.4～2.56GHz）,在5GHz频段的可达1.32GHz（5.05～6.37GHz）。整个天线在42mm×52mm、介电常数为4.5、厚度为1.5mm的FR4介质基片上实现。结果表明,该天线具有十分良好的应用潜质。     

Flexible design and implementation of QC-Based LDPC decoder architecture for on-line user-defined matrix downloading and efficient decoding

This paper proposes a flexible QC-LDPC decoder to support on-line matrix downloading. Its applications include IEEE 802.16e, 802.11n/ac/ax, and other advanced standards. Via TSMC 40-nm technology, the flexible architecture only has an area of 0.415 mm². The according power dissipation is 84.68 mW at maximal clock frequency of 1.0 GHz. It is successfully verified with 3 LDPC codes pre-defined in IEEE 802.11n/ac/ax.     

Broadband circularly-polarised microstrip antenna with switchable polarisation sense

A circularly-polarised microstrip antenna capable of switching polarisation sense is presented. The proposed microstrip antenna has a circular radiating patch and is excited by an open-loop microstrip line through the coupling of a ring slot in the ground plane. Two ends of the open-loop microstrip line can be taken for the input ports to excite right-hand and left-hand circular polarisations, respectively. A prototype using PIN diodes to electrically switch the input ports is implemented, and the measured results show the 3 dB axial ratio bandwidth of more than 10% can be obtained at the two polarisation senses     

Eight Element Low-Cost Microstrip MIMO Antenna for Wi-MAX and 5G Applications

Wireless Personal Communications - In this communication, a low-cost four/eight-element MIMO antenna is proposed for Wi-MAX (IEEE 802.16d) and 5G applications band. A reverse U-shaped slot is...     

一种新型陷波特性超宽带天线设计

为了满足现代通信的需求,设计了一种新型的超宽带平面天线,实现了良好的超宽频带阻抗匹配.该天线的辐射贴片与接地板结构相似,通过在辐射贴片上加载U型槽以及在馈线一侧加载新型陷波结构分别在中心频率3.5 GHz和5.5 GHz处产生陷波.天线实测与仿真结果基本相近,通带内辐射效果良好,且该天线对WIMAX及WLAN波段有很好的抑制功能,可用于超宽带系统.     

Broadband circularly polarised crosspatch- loaded square slot antenna

A new design of a circularly polarised square slot antenna loaded with a cross patch is presented. A cross patch inclined diagonally with respect to the square slot is placed at the centre of the square slot. By choosing proper dimensions of the cross patch, two orthogonal resonant modes with a 90deg phase difference for circular polarisation can be excited and feed the square slot antenna using a 50 Omega CPW with a protruded signal strip. 10 dB return loss bandwidth of 846 MHz (39.6%) and 3 dB axial ratio bandwidth of 240 MHz (12.4%) for the proposed antenna are achieved. Gain variation within the CP bandwidth is observed to be less than 1 dB     

Development of wideband CPW-fed hexagon-shaped circularly polarized slot antenna for wireless-communications

A hexagonal shaped circularly polarized (CP) wideband slot antenna using multiple stubs has been proposed and investigated. A hexagonal slot is created in the ground plane with tapered sections improving the impedance matching. Two radiators are incorporated in the structure, which is responsible for generating orthogonal degenerate modes; hence, CP radiation is achieved for the proposed antenna. For enhancing the gain of antenna, one radiator is directly connected to feed line and another one embedded in the ground plane. An inverted L-shaped arm is inserted in the slot to enhance and tune the circular polarized behavior. The presented radiator have input reflection coefficient ranges from 5.67 to 8.50 GHz (39.97%) and axial ratio bandwidth (ARBW) of 5.60–8.50 GHz (41.13%). The proposed antenna provides overlapping bandwidths of 5.67–8.50 GHz (39.97%) having average gains of 5.25 dBi within the entire frequency bands. The presented antenna is exceptionally good for the application of mobile and satellite communications.     

Design of a compact U-shaped slot triple band antenna for WLAN/WiMAX applications

This article presents a small, low-profile planar microstrip antenna that is applicable for both WLAN and WiMAX applications. The goal of this paper is to design an antenna which can excite triple-band operation with appreciable impedance bandwidth to combine WLAN/WiMAX communication specifications simultaneously in one device. The designed antenna has a compact size of 10 × 26 mm². The proposed antenna consists of an inverted U-shaped slot radiator and a defected ground plane. Overall the design method and parametric study found appropriate dimensions, which provides three distinct bands I from 2.40 to 2.52, II from 3.40 to 3.60 and III from 5.00 to 6.00 GHz that covers entire WLAN (2.4/5.2/5.8 GHz) and WiMAX (2.5/3.5/5.5) bands. Finally, a prototype antenna was fabricated and experimentally characterized to verify the design concept as well as to validate the simulation results. Thus the simulation results along with the measurements show that the antenna can simultaneously operate over WLAN and WiMAX frequency bands.     

A printed dual-wideband magneto-electric dipole antenna for WWAN/LTE applications

A planar-printed dual-wideband U-shaped magneto-electric dipole omnidirectional antenna with a composite feeding structure for WWAN/LTE applications is proposed. Firstly, a U-shaped electric dipole structure is presented to provide a dual-wideband by changing the surface-current distributions. In addition, in order to reduce antenna size and improve impedance matching, a new feeding structure designed with inverted U-shaped tapered line and meandering T-shaped line is introduced. Finally, instead of a conventional vertical ground plane, a small-size one is printed on the reverse side of the substrate to achieve stable gains and omnidirectional radiation patterns. The antenna prototype can attain a bandwidth of 35.8% (0.78–1.12 GHz) with a stable gain of 3 ± 0.5 dBi for the lower band, and a bandwidth of 50.5% (1.66–2.78 GHz) with a gain of 3.8 ± 0.6 dBi for the upper band, covering the frequency bands granted for WWAN/LTE systems. To the best of our knowledge, it is the first real-sense planar magneto-electric dipole antenna proposed. In comparison with the existing ME dipole antennas, the proposed antenna, which is planar-printed on a small-size FR4 substrate with a simple structure, can be easily fabricated at low cost and thus is promising for WWAN/LTE communication.