Dual-sense Circularly Polarized Research Articles

Compact Self-Diplexing Dual-Band Dual-Sense Circularly Polarized Array Antenna With Closely Spaced Operating Frequencies

A novel self-diplexing aperture-shared dual-band dual-sense circularly polarized (CP) antenna array is proposed for transmitting/receiving (Tx/Rx) applications in X-band satellite communication systems. The antenna is capable of receiving the left-handed CP (LHCP) signals in the low band while transmitting the right-handed CP (RHCP) signals in the high band. First, a dual-port cavity-fed linearly polarized (LP) patch antenna with high isolation is developed as the element of the array. The element is composed of a slotted patch, a U-slot loaded substrate integrated cavity (SIC), and two groups of split-ring resonators (SRRs). The LHCP and RHCP operations are achieved by employing two sequentially rotated feeding networks which are isolated by a ground plane. To reduce the mutual coupling between the radiators, narrow slots are etched out in the center of the patches. Importantly, the sharing of patches at different bands (i.e., common aperture) enables a compact footprint to be achieved for the array, which is beneficial for suppressing undesirable grating lobes due to the reduced interelement spacing. The measured results of a fabricated prototype agree well with the simulations, showing an impedance bandwidth of 7.2–7.75 GHz (7.85–8.4 GHz), 3 dB axial ratio (AR) bandwidth of 7.4–7.7 GHz (7.95–8.32 GHz), and gain of 14 dBic (14.2 dBic) at the low band (high band). The channel isolation is over 27 dB and the sidelobe levels are below −15 dB in both bands. The demonstrated low-profile dual-band, dual-sense CP antenna array can be a good candidate for satellite communication.

Simple Reconfigurable Circularly Polarized Antenna at Three Bands.

In this paper, a simple design for a triple-band circularly polarized (CP) antenna with the capability of switching its polarization between dual-sense CPs is presented. The proposed antenna is comprised of a monopole loop antenna as a primary radiator. By placing a parasitic loop around the primary radiator, an additional CP band is achieved. Reconfigurability of the polarization between right-hand CP (RHCP) and left-hand CP (LHCP) at three different frequencies of 2.5, 3.3, and 3.8 GHz was realized by controlling the ON/OFF states of two PIN diodes. For validation, the fabricated antenna yielded an impedance bandwidth of 52.6% (2.34–4.01 GHz), while the axial ratio bandwidths for both the RHCP and LHCP states were 3.5% (2.47–2.56 GHz), 6.6% (3.20–3.42 GHz), and 2.4% (3.74–3.83 GHz). The measured broadside gains within the axial ratio bandwidth were 1.2, 2.7, and 1.4 dBi, respectively. Compared to other reconfigurable multi-band CP antennas, the proposed design is the first work to achieve a reconfigurable polarization at three distinct bands at a low fabrication cost by using only two diodes. The proposed antenna is suitable for WLAN and WiMAX applications.

Compact Single Feed Dual Band Microstrip Patch Antenna with Adjustable Dual Circular Polarization

This paper presents a novel dual-band, half E-shaped microstrip patch antenna (HEMSPA) with dual sense polarization. The proposed antenna covers two different frequency bands and radiates electromagnetic waves with left hand circular polarization (LHCP) and right hand circular polarization (RHCP) at lower and upper frequency bands, respectively. The dual frequency is realized by etching four T slits close to the radiating edges of HEMSPA. A shorting bar is adopted to attain LHCP waves at lower band while a vertical slot etched in the patch center aids in achieving RHCP waves at upper band. The proposed antenna has a small frequency ratio of 1.2 and good scalability. It can be easily re-designed for other operating frequencies with dual sense circular polarization (CP) or same sense CP at dual frequencies. The simulated reflection coefficient, axial ratio, and radiation pattern characteristics show a good agreement with the experimental data for dual-band performance. The measured −10 dB impedance bandwidth, 3 dB axial ratio bandwidth, and boresight gain are observed to be 1010 MHz, 70 MHz, 9.27 dBic and 120 MHz, 69 MHz, 6.63 dBic in the lower band, and upper band, respectively. The proposed antenna would be promising for modern wireless communication system applications.

X-Band Dual Circularly Polarized Patch Antenna With High Gain for Small Satellites

This paper presents an X-band circularly polarized patch antenna with a simulated high gain of 12.5 dBi and a simulated side-lobe-level of below −20 dB, within the bandwidth of 5.2%. This single element antenna achieves high gain by exploiting the mode superposition of TM11 + TM13 (excited by a circle of vias loading the cavity) and TM12 + TM14 (excited by the cavity itself) radiated from the two apertures, respectively. A simple feeding network, consisting of a quadrature hybrid and a couple of 90° bent branches, is used in the design to excite RHCP or LHCP mode in the antenna cavity. A capacitive disk feeding is implemented so that the antenna can be matched to the feeding network, and the super-positioned fields inside the cavity are not disturbed by the feeding pins. This approach makes the design of a dual-sense circularly polarized antenna with high gain easier since the array configuration is not needed. High gain, in combination with a dual-sense circular polarization, makes the proposed antenna particularly attractive for space applications involving small satellites. With the proposed design, it is possible to employ only one antenna rather than two (RHCP and LHCP), thus saving space on the aircraft, which is clearly a limited resource.

A Quad-Band Dual-Sense Circularly-Polarized Square-Ring Antenna for Multi-Functional Wireless Applications

A quad-band dual-sense circularly-polarized (CP) antenna is presented for multi-functional wireless applications. Initially, the corner-fed square-ring radiator is designed with one end open-circuited. The surface currents flow along the circumference of the square-ring, which excite dual-band dual-sense CP radiation with a right-hand circular polarization (RHCP) at one frequency band and a left-hand circular polarization (LHCP) at the other band. Later, a rhombic-shaped slot and an inverted V-shaped parasitic element, used to balance the surface currents in horizontal and vertical directions at the middle and low frequency regions, excite two additional LHCP bands. The proposed antenna is systematically presented through a CP generation principle, a surface current distribution, and parametric analysis. The measured results yield an impedance bandwidth (IBW) of 83.9% (2.33–5.70 GHz) and the 3-dB axial ratio bandwidths (ARBWs) of 7.3% (2.38–2.56 GHz), 9.0% (2.75–3.03 GHz), 3.7% (3.42–3.53 GHz), and 7.1% (5.16–5.54 GHz). The maximum broadside gains achieved within the axial ratio bandwidths are 2.5, 2.9, 3.4, and 2.7 dBi, respectively. Compared to other reported works considering quad-band CP radiation, the proposed antenna achieves a wider ARBW and smaller size. To the best of the author’s knowledge, the proposed work is the first paper presenting a planar quad-band dual-sense CP antenna for WLAN (2.5/5.3 GHz), WiMAX (3.5 GHz), and Marine Service (3.0 GHz) wireless applications.

A Left/Right-Handed Dual Circularly-Polarized Antenna With Duplexing and Filtering Performance

A shared-radiator dual-band dual-sense circularly-polarized (CP) microstrip antenna with duplexing and filtering functions is presented. For each band, there is a coupling network, which consists of a hairpin resonator, a straight slot, and a U-slot, and thus two paths with an inherent 90° or −90° phase difference are available for the input signal to couple to the patch, left-handed CP (LHCP) characteristic and right-handed CP (RHCP) characteristic are respectively realized at different bands for the proposed antenna with a single patch. Such a dual-band dual-sense CP patch antenna is highly integrated and outperforms other traditional CP antennas state-of-the-art. Moreover, the duplexing and filtering functions are seamlessly integrated into the dual-band patch antenna with a low-profile ( $0.044\lambda _{o}$ ), and application of such an integrated device in wireless systems can potentially reduce the volume, complexity, and cost of RF front-ends. Based on resonator-based topologies, the principles of achieving the dual-sense CP, duplexing, and filtering functions are illustrated. As a proof-of-concept, an antenna working at C-band is prototyped and tested. Good agreements between the measured and simulated results are achieved, showing an LHCP radiation characteristic for the low-band operation and a RHCP radiation characteristic for the high-band operation, respectively. The antenna also exhibits very good frequency selectivity and out-of-band rejection performance. At the low-band, the impedance and 3-dB axial-ratio (AR) bandwidths are 4.7% and 1.1%. At the high-band, the impedance and AR bandwidths are about 7.3% and 3.2%. The isolation between the two channels/bands is over 24 dB.

A Tilted-D-Shaped Monopole Antenna With Wide Dual-Band Dual-Sense Circular Polarization

In this letter, a tilted-D-shaped monopole antenna with wide dual-band dual-sense circular polarization is proposed. The tilted-D-shaped radiator is designed by combining the inverted-C-shaped (ICS) and tilted-I-shaped (TIS) structures. The proposed radiator is attached to a 50 $\Omega$ line through an impedance transformer. The proposed design is compared with two of its variants, which concludes that the wide 3 dB axial ratio bandwidth (ARBW) in both bands is achieved due to the contributions from the ICS and TIS structures. Besides, the lower and upper bands radiate left-handed circular polarization and right-handed circular polarization, respectively. A prototype of the proposed antenna is fabricated, and its performance is experimentally verified. The measurement results show that the proposed antenna exhibits a wide impedance bandwidth for $\mathopen |$ S $_{11}\mathclose | $-$ 10 dB of 104.54% (3.47–11.07 GHz) entirely covering both circularly polarized bands with 3 dB ARBWs of 31.16% (4.28–5.86 GHz) in the lower and 22.62% (7.49–9.4 GHz) in the upper band. In broadside direction, the measured gain varies between 1.26–3.58 dBic and 3.85–6 dBic in the lower and upper bands, respectively.

A Simple Design of Compact Dual-Wideband Square Slot Antenna With Dual-Sense Circularly Polarized Radiation for WLAN/Wi-Fi Communications

A novel compact dual-wideband, dual-sense, circularly polarized (CP), square slot antenna with the simple structure is presented in this communication. The right-hand circular polarization in the +z-direction for the lower frequency is mainly realized by an inverted L-shaped strip, and the left-hand circular polarization in the +z-direction for the upper frequency is mainly achieved by an offset feed structure. A parasitic matching stub is helpful to improve the input impedance matching. The overall dimension of the prototype is only $50 \times 50 \times 1~\text{mm}^{3}$ . An optimized antenna is fabricated and measured. The measured 10 dB return loss bandwidth is 111% (1.82–6.36 GHz). Its measured 3 dB axial-ratio bandwidths in the broadside direction are 55% (1.91–3.36 GHz) at lower band and 29.3% (4.78–6.41 GHz) at upper band, which can fully cover all the wireless local area network and wireless fidelity bands. What is more, this antenna has stable antenna gain and good radiation patterns within these two CP bands.

Design of Dual Band Dual Sense Circularly Polarized Wide Slot Antenna with C-shaped Radiator for Wireless Applications

Abstract A low profile wide slot antenna for dual band and dual sense circular polarization (CP) is proposed here and is simulated by using HFSS simulation software.The proposed antenna having a C shaped patch for dual band operation and a wide square slot etched on the ground with two strips for CP operation. In between radiating patch and ground plane, designed antenna has a layer of easily available dielectric (FR-4) material. Proposed antenna shows an impedance bandwidth of 13.8 % at 2.38 GHz of centre frequency and 9.7 % at 4.43 GHz of centre frequency for lower and upper band respectively. The 3-dB axial ratio (AR) bandwidths for lower and upper band are 18.8 % (at 2.44 GHz of centre frequency) and 13.3 % (at 4.29 GHz of centre frequency), respectively. The peak gain for the lower and upper band is found as 4.1 dBi and 3.3 dBi, respectively. A close agreement has been found between the simulated and the measured results.

A quad‐band dual‐polarized monopole antenna for GNSS/UMTS/WLAN/WiMAX applications

AbstractA quad‐band dual‐polarized monopole with asymmetrical microstrip feed line is proposed in this article. The proposed antenna exhibits a linearly polarized behavior in three operating bands for UMTS, WLAN 2.4 GHz, and WiMAX 3.5 GHz applications while a circularly polarized nature in the lowermost band for the GPS/GLONASS. The multiband operation is achieved because of λ/4 mode of resonances of three different monopole lengths and 3λ/4 mode of longer monopole. The 3λ/4 mode of larger monopole is controlled by using an L‐Shaped stub to make it useful for WiMAX application (3.5 GHz). The circular polarization for GPS (band‐L1, 1575 MHz) is achieved by using an L‐shaped slit with the ground plane which leads to generation of magnetic current orthogonal to the longest monopole current corresponding to the lowermost resonance frequency. The proposed antenna exhibits impedance bandwidths of 11.22%, 7.9%, 6.84%, and 4.26% at the resonant frequencies of 1.5, 2.02, 2.46, and 3.51 GHz, respectively. The axial ratio bandwidth corresponding to the GPS band is 2.5%. The proposed antenna has dual sense circular polarization (LHCP in θ = 0° and RHCP in θ = 180°) and bi‐directional radiation patterns at GPS/GLONASS band along with stable gain and good efficiency in all the operating bands.

Dual-Band Annular Slot Antenna Loaded by Reactive Components for Dual-Sense Circular Polarization With Flexible Frequency Ratio

This paper proposes a new design of dual-band reactively loaded annular slot antenna for dual-sense circular polarization radiation. Two concentric annular slots excited by a common microstrip feedline are employed to realize dual-band operation. Each slot can radiate a circularly polarized (CP) wave with a specified sense at its one or one-and-a-half wavelength resonance, given that an appropriately valued reactive component, i.e., capacitor or inductor, is introduced at a pre-determined location. A small frequency ratio (FR) can be achieved between the two oppositely sensed CP bands when a capacitor and an inductor are loaded, respectively, onto the inner and outer annular slots. Contrarily, two oppositely sensed CP bands that possess a large FR can be yielded when an inductor and a capacitor are loaded onto the inner and outer annular slots, respectively. For experimental verification, two antenna prototypes with FRs of 1.63 and 2.41 have been designed, fabricated, and measured. The measurement results exhibit a good agreement with the simulated ones. Details of design concerns and experimental results are presented and discussed.

Coplanar waveguide fed multiple input multiple output antenna with higher isolation and multi-sense circular polarization

A coplanar waveguide (CPW)-fed multiple input multiple output (MIMO) antenna with higher isolation and multi-bandwidth circular polarization (CP) is presented. This antenna covers the impedance operations from 2.2 to 6.8 GHz with < −10 dB, < −14 dB and < −10 dB. Employing two orthogonally placed T-shaped patches (TSP) and three L-shaped parasitic patches (LSPP) in the ground, the dual sense CP in the frequency band between 2.28 and 3.48 GHz (42.5%) and meanwhile between 6.03 and 6.28 GHz (4.1%) can be achieved when the left port (port_1) is excited, while the down port (port_2) is terminated by a 50 Ω load. When Port_2 is excited and port_1 is terminated by a 50 Ω load, the CP of the antenna in frequency band from 1.75 to 2.1 GHz (18.2%). On the other hand, CP from 4 to 4.47 GHz (11.1%) and 5.1 to 5.22 GHz (2.3%) can be obtained while both ports are excited. The CP frequency band covers the frequency bands for LTE (between 1.71 and 2.17 GHz), the WCDMA (between 1.92 and 2.17 GHz), the WiMax (between 2.3 and 2.5 GHz) and the WLAN. Meanwhile, the slot between these two TSP in the ground enhances the isolation of the proposed antenna. The measured and the simulated results are agreed with each other.

Compact Broadband Dual-Sense Circularly Polarized Microstrip Antenna/Array With Enhanced Isolation

This paper presents a novel method of designing the compact dual-sense circularly polarized (CP) microstrip antenna/array with improved impedance bandwidth, axial ratio (AR) bandwidth, and interpolarization isolation. The left-hand and right-hand CP characteristics are achieved simultaneously by conceiving a vertically coupled resonant structure for the first time. Different from traditional methods, the antenna shows a compact size but exhibits the wide impedance and 3 dB AR bandwidths. For each input, two coupling paths are purposely designed to excite the TM10 and TM01-mode of the patch, respectively. By composing different coupling units in the two paths, an intrinsic ±90° phase difference over a broadband can be obtained, resulting in the broadband CP characteristics. In addition, a novel method of using the neutralization line between the two feeds is investigated to improve the isolation between the polarizations. Based on the dual-sense CP element, a $1 \times 4$ dual-sense CP array is composed to exemplify its potential applications in large arrays. Compared with traditional CP antennas, the proposed antennas have the advantages of compact size, simplified feed, broad impedance and 3 dB AR bandwidths, and improved isolation. Experimental results verify the predictions.

Dual-Band Magnetoelectric Dipole Antenna With Dual-Sense Circularly Polarized Character

In this paper, a dual-band dual-sense circularly polarized (CP) magnetoelectric dipole antenna is proposed. The antenna consists of a cavity reflector, two pairs of vertical and horizontal copper plates, and a crossed $\Gamma $ -shaped feeding structure. The shorted vertical plates work as quasi-magnetic dipoles (M-dipoles), while the connected horizontal plates work as electric dipoles (E-dipoles). Two M-dipoles and E-dipoles are designed to possess different heights and lengths, and thus they are able to achieve separate operation bands. To generate dual-sense CP performance, the M-dipoles and E-dipoles are placed in parallel and the adjacent E-dipoles extend along the opposite directions. Benefiting from the intrinsic 90° phase difference between the M-dipole and E-dipole, the left-hand CP is achieved within the lower operation band (2.15–3.4 GHz) and the right-hand CP is achieved within the upper band (4–6.3 GHz). The proposed antenna possesses a unidirectional radiation pattern with high front-to-back ratio ( $\ge 22$ dB). Furthermore, high gain ( $\ge 8$ dBi) and radiation efficiency ( $\ge 90$ %) are also achieved.

Dual-band capacitively loaded annular-ring slot antenna for dual-sense circular polarization

This paper investigates a simplified and new capacitively loaded annular-ring slot antenna (ARSA) for dual-band and dual-sense circular polarization. The antenna is comprised of two concentric annular-ring slots coupled to a microstrip feed line to achieve dual-band operation. With introducing proper distributed capacitances fulfilled by two closely spaced T-shaped arc strips across the outer and inner annular-ring slots at opposite positions with respect to the microstrip feed line, the dual-sense circular polarization can hence be obtained. The antenna features that the impedance and circular polarization characteristic for the upper band can be independently adjusted. Numerical analysis and experimental validation have been carried out. The measured 10-dB return loss impedance bandwidths for both bands are greater than 22.0%. The measured 3-dB axial ratio (AR) bandwidths are 3.6 and 5.6%, respectively, for the lower and upper bands.

A triple band circular polarized monopole antenna for GNSS/UMTS/LTE

ABSTRACTA circularly polarized Y‐shaped monopole antenna with L‐shaped slot loaded ground‐plane is proposed in this letter. The multi‐band operation is achieved due to the resonances of asymmetrical monopole arms as well as the slot in the ground plane. The circular polarization for LTE (band‐7, 2600 MHz) is achieved by using orthogonal and out of phase currents on surface of Y shaped monopole, whereas circular polarization for GNSS and UMTS‐2100 bands is the result of interaction of currents on longer arm of Y shaped monopole and loop currents on ground, which acts as a magnetic monopole. The antenna has been designed and optimised on a low cost FR‐4 epoxy substrate. The proposed antenna exhibits impedance bandwidths of 13.1, 9.7, and 7.4% at the resonant frequencies of 1.57, 2.02, and 2.55 GHz, respectively. At these three resonances, 3 dB axial ratio bandwidths of 3.7, 4.9, and 5.06% are achieved. The antenna has dual sense circular polarization, bidirectional radiation patterns, stable gain and good efficiency in the operating bands. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:298–304, 2017

A SINGLE-FEED DUAL-BAND DUAL-SENSE CIRCULARLY POLARIZED MICROSTRIP ANTENNA

A single-feed dual-band dual-sense circularly polarized (CP) microstrip antenna is proposed. The antenna consists of a circular radiating patch with a ring slot, two substrates with an air layer sandwiched between them and a capacitive coupling feed. The two resonant frequencies are controlled by the size of the circular radiating patch and the ring slot. By introducing the perturbation, the fundamental resonant mode splits into two orthogonal degenerate modes, and the CP radiation pattern is obtained. Capacitive disk coupling feed is also used in the design to enhance the bandwidth. The key parameters of the design are investigated to show how to obtain dual-band and dual-sense CP. The proposed antenna prototype is fabricated and measured, and experimental results show that good CP radiation performances are obtained at both resonant frequencies.

DUAL-BAND DUAL-SENSE CIRCULARLY POLARIZED SLOT ANTENNA WITH AN OPEN-SLOT AND A VERTICAL STUB

A new dual-band dual-sense circularly polarized (CP) slot antenna is designed in this paper. The proposed antenna is composed of a rectangle patch and a modifled ground plane. By opening a U-shaped open-slot and loading a vertical stub to the ground plane, a dual-sense CP performance is achieved for two frequency bands. A bevel is cut on the patch to improve the impedance matching. The antenna is fabricated on a low-cost FR4 substrate and fed by a coplanar waveguide (CPW) structure. The antenna has been investigated numerically, and a prototype was experimentally measured. Experimental results show that the measured 10-dB return loss impedance bandwidths are 18.3% (2.72{3.27GHz) for the lower band and 23.7% (4.65{5.90GHz) for the upper band, and the measured 3-dB axial ratio (AR) bandwidths for the lower and upper bands can be up to 28.4% (2.48{3.30GHz) and 26.3% (4.63{6.03GHz), respectively.

DESIGN OF DUAL-BAND DUAL-SENSE CIRCULARLY POLARIZED SLOT ANTENNA

Based on a construction of concentric deformed annular slots with a stepped microstrip feed line, two designs of dual-band dual-sense circularly polarized slot antenna are proposed in this paper. Compared with the flrst antenna, the second design possesses the merits of simple structure by devising a twin-slot with less adjusted parameters to achieve the same satisfactory output responses. The results from simulations and measurements demonstrate that both of the antennas have good quality of impedance matching and dual-sense circular polarization at 1.6GHz and 2.5GHz.

Dual-Frequency Dual-Sense Circularly-Polarized Slot Antenna Fed by Microstrip Line

A new design of a dual-frequency dual circularly-polarized slot antenna is presented. The dual-frequency is achieved using a single-layer microstrip-fed configuration coupled to a modified annular-slot antenna. The dual sense circular-polarization is obtained by four unequal linear slots which augment the annular slot. Experimental results show the proposed antenna has good circular polarization characteristics for both right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP). The 10 dB return loss impedance bandwidths for the lower (RHCP) and higher (LHCP) bands are 26.7% and 11.3%, respectively. The 3 dB axial-ratio bandwidths are 6.1% and 6.0% with respect to 1.5 GHz (RHCP) and 2.6 GHz (LHCP), respectively.