Dual-polarized Slot Antenna Research Articles

Development and Application of Dual-Polarization Antenna for Dielectric Logging Sensor.

Because the dielectric constant of water is greater than that of oil and gas, dielectric logging sensors can effectively distinguish oil and gas reservoirs from water layers by measuring the dielectric parameters of formations. Under the special working conditions during the logging of boreholes drilled for oil and gas exploration, such as high temperature and pressure and a narrow working space, the endurance and effectiveness of the antenna in the dielectric logging sensor are crucial. This paper presents a design method for a dual-polarization slot antenna for such working conditions. We theoretically analyzed the working principle of this antenna, established the antenna model, and evaluated its radiation characteristics through simulation. Subsequently, we developed and tested the proposed antenna. The antenna could withstand a high temperature and pressure of 175 °C and 140 MPa, respectively. A dielectric logging sensor using the proposed antenna was successfully applied in oilfield logging.

Shared-Radiator Design of Dual-Band Coplanar Base Station Antenna Array Using Cavity-Backed Slots

In this communication, we propose a shared-radiator design concept for dual-band base station antenna arrays. To realize the concept, novel differentially fed dual-polarized slot antenna is devised to be the high-band (HB, 3.4–3.6 GHz) radiator, while the large slot ground can be reused as the radiating arm of the low-band (LB, 0.69–0.96 GHz) crossed dipole. Reflective cavities are introduced to back the HB antennas, building clear and independent radiating environments for the two operating bands. A dual-band base station antenna array with one LB dipole antenna and four HB slot antennas is designed, by adopting the proposed integration concept. Good impedance matching (voltage standing wave ratio <1.5) and high port isolation (>29.5 dB in the LB and >26.6 dB in the HB) are obtained. Stable radiation patterns are also achieved in the two bands.

Dual-Polarized Slot Antenna for Full-Duplex Systems With High Isolation

A single-layered slot antenna system working at 5.8 GHz Industrial, Scientific and Medical (ISM) band is proposed for in-band full duplex (IBFD) operation applications without the use of a coupler. First, high isolation is achieved by strong separation of even- and odd-mode feeds. The microstrip-coupled coplanar waveguide (CPW) is used at Port 1 (TX port) to excite a stepped-slot antenna in the CPW odd mode. On the opposite side, a microstrip T-junction power divider is employed at Port 2 (RX port) to feed two offset-fed stepped-slot antennas in even mode. Second, isolation is further improved by 30 dB by using a lumped capacitor at the termination of the CPW. The measured isolation between the two ports is about 50 dB across the bandwidth. The measured −10 dB bandwidth of Port 1 is 0.49 GHz (8.5%), while that of Port 2 is 1.06 GHz (18.3%). The gains of TX and RX antennas are 5.4 and 5.8 dBi at 5.8 GHz. The proposed antenna can also be deployed as a dual-polarized antenna. Mathematical analysis and equivalent transmission line circuit models are provided to give physical insight into the working principals of the antenna with validation from ANSYS HFSS simulation.

Design of Dual Polarized Slot Antenna for UWB Communications

The design presents the dual-polarized antenna, which works on an ultra-wideband range of 3.1GHz to 10.1GHz. The overall configurations is square, with two adjacent arms being micro strip fed that are orthogonal to each other and are accountable for two opposite polarized fields. Two other slots are put in symmetry to minimize cross-polarization. The simulated impedance bandwidth is 10 GHz (from 3.1GHz to 10.1GHz) mainly in the UWB range. The 20 dB isolation is achieved from 4.2 GHz to 9.9 GHz. The mutual coupling between the two slots begins from 3.4 GHz. With good isolation and less cross-polarization, the MIMO antenna works very well in many UWB applications such as automotive radars, imaging, wearable devices, and wireless communication.

A Triband SIW Cavity-Backed Differentially Fed Dual-Polarized Slot Antenna for WiFi/5G Applications

A tri-band differentially fed dual-polarized slot (DFDPS) antenna is developed for indoor WiFi/5G wireless communications. The triband antenna is made up of two crossed slots with four pairs of L-shaped slots. The lower and higher bands are generated by the crossed slots, and the middle band is attributed to the L-shaped slots. Eight shorting pins are introduced for improving the impedance matching for all the three bands. A substrate-integrated waveguide (SIW) cavity is employed to back the antenna for unidirectional radiation. Two orthogonal feedlines are applied to differentially feed the antenna for dual polarization. The antenna has a low-profile of about $0.054~\lambda _{\mathbf {2.4}}$ , where $\lambda _{\mathbf {2.4}}$ is the wavelength at the lowest frequency of 2.4 GHz in free space. It is shown that the triband antenna can operate in three bands of 2.4–2.51, 3.29–3.6, and 4.8–5.05 GHz with good unidirectional patterns.

A Miniaturized Dual-Band Dual-Polarized Band-Notched Slot Antenna Array With High Isolation for Base Station Applications

In this article, a miniaturized dual-band dual-polarized slot antenna array is proposed for base station applications. It consists of two closely located $1 \times 4$ subarrays for the digital cellular system (DCS) and wideband code division multiple access (WCDMA) operations. The band-notched slot antenna (BNSA) is designed and adopted as the subarray element with radiation-suppression characteristic at notch frequencies. The notch frequency for one subarray is designed at the center operating frequency of the other subarray. As a result, the radiation from DCS subarray could be effectively suppressed within the WCDMA band and vice versa, resulting in high isolation between two subarrays with a small separation distance. By using the artificial magnetic conductor (AMC) reflector, the array height could be reduced by half, as compared with the perfect electric conductor (PEC) counterpart. In addition, a four-way unequal power divider is designed for the array's beam-pattern synthesis. For the demonstration, the proposed array is fabricated and measured. The measurement results show that the dual-band array achieves the impedance bandwidths of 1.65-1.88 and 1.89-2.22 GHz, the isolations over 25 dB, the realized boresight gains of 12.2-12.8 and 12.3-13.2 dBi, and the sidelobe levels below -18 dB. The results indicate that the proposed array is a promising candidate for base-station applications.

A Differentially Fed Dual-Polarized Slot Antenna With High Isolation and Low Profile for Base Station Application

In this letter, a low-profile differentially fed dual-polarized slot antenna is proposed for base station application. Its radiator is an octagon patch etched with two normal H-shaped slots. The folded feeding line is introduced to accommodate the differentially fed scheme and tune impedance matching. Both high isolation and stable radiation patterns are realized by using the differential feeding technique. Measured results demonstrate that the impedance bandwidths (VSWR <; 1.5) of the two polarizations are 19.3% (3.14-3.81 GHz) and 20.3% (3.10-3.80 GHz), respectively. The proposed antenna has a high isolation of larger than 43 dB over the entire operation band. The measured gain is higher than 8.1 dBi within the operating frequency.

Bandwidth Enhancement of a Dual-Polarized Slot Antenna Using Characteristic Modes

In this letter, a wideband dual-polarized slot antenna is presented. The proposed antenna is designed in a systematic way using the theory of characteristic modes for slot apertures. An H-shaped slot in an infinite ground plane is used as the initial structure for further optimization design. Magnetic characteristic currents for the first four modes of the slot are investigated. To enhance the bandwidth (BW) of the antenna, the geometry of the slot antenna is then modified based on the clear physical insights obtained from the modal analysis. In addition, two pairs of differentially fed capacitive coupling elements are introduced to excite the first two modes of the slot, and an integrated wideband feeding network is designed. An antenna prototype in WLAN 2.4 GHz band is fabricated. Experimental and simulated results show that the proposed dual-polarized slot antenna has a wide BW and good dipole-like radiation characteristics. Compared with the initial H-shaped slot antenna, the BW of the proposed antenna is enhanced from 17% to 46%. The measured port isolation over the entire frequency band is about 26 dB, and the cross-polarization level is over 28 dB for the two polarizations.

A Compact Wideband Dual-Polarized Slot Antenna With Five Resonances

This letter presents the design and analysis of a compact dual-polarized slot antenna using a triple-mode stepped slot-line resonator and a dual-mode cross-shaped monopole. The orthogonal polarization is achieved by feeding the two ports symmetrically at the opposite positions of the slot. All the five resonance frequencies can be flexibly adjusted by tuning different dimension parameters, so by increasing the frequency difference between the five resonance modes, a very wide common operating band (1.63-2.93 GHz) is obtained and also with a high port isolation (<; -32 dB). Finally, by loading two grounded lumped capacitors on the cusp sections of the monopole, its second resonance frequency can be independently reconfigured.

Wideband Dual Polarization Slot Antenna With High Isolation By Using Microstrip Line Balun Feed

A wideband dual-polarization slot antenna with high isolation is proposed in this letter. This double-layer antenna consists of two pairs of parallel microstrip line baluns etched on the top surface of the upper layer and bottom surface of the lower layer, respectively. Four circular radiating units are sequentially set in each center of four circular slots on the middle surface between two layers. The dual-polarization characteristic is achieved by exciting two orthogonal capacitive-coupled circular dipole modes. The proposed antenna is fabricated and tested. The measured results show that relative impedance bandwidths of the two ports are 55.9% (2.40–4.26 GHz) and 52.8% (2.40–4.12 GHz). The port isolation is below –35 dB and the cross-polarization level is below –20 dB across the whole band.

Broadband Dual-Polarization and Stable-Beamwidth Slot Antenna Fed by U-Shape Microstrip Line

A novel broadband dual-polarized slot antenna with stable radiation pattern is presented. Two U-shape microstrip lines are introduced at two feeding ports to excite a cross-shape slot for realizing dual-polarized antenna. The simulated results are given to explain how the ground plane, short metallic pillars, and reflector affect the reflection coefficient, $\vert S_{11}\vert $ . The beamwidth of the proposed antenna is stable within the operating band, whereas a broad fractional bandwidth ( $\vert S_{11 }\vert dB) up to 68% is achieved, covering a frequency range of 1.3–2.65 GHz. The measured half-power beamwidth of ${H}$ -plane is 66.8° ± 3.4°.

Wideband, Low-Profile, Dual-Polarized Slot Antenna with an AMC Surface for Wireless Communications

A wideband dual-polarized slot antenna loaded with artificial magnetic conductor (AMC) is proposed for WLAN/WIMAX and LTE applications. The slot antenna mainly consists of two pairs of arrow-shaped slots along the diagonals of the square patch. Stepped microstrip feedlines are placed orthogonally to excite the horizontal and vertical polarizations of the antenna. To realize unidirectional radiation and low profile, an AMC surface composed of 7 × 7 unit cells is designed underneath a distance of 0.09λ0 (λ0 being the wavelength in free space at 2.25 GHz) from the slot antenna. Both the dual-polarized slot antenna and the AMC surface are fabricated and measured. Experimental results demonstrate that the proposed antenna achieves for both polarizations a wide impedance bandwidth (return loss 10 dB) of 36.7%, operating from 1.96 to 2.84 GHz. The isolation between the two input ports keeps higher than 29 dB whereas the cross-polarization levels basically maintain lower than −30 dB across the entire frequency band. High front-to-back ratios better than 22 dB and a stable gain higher than 8 dBi are obtained over the whole band.

A Dual-Polarized Square-Ring Slot Antenna for UWB, Imaging, and Radar Applications

In this letter, a dual-polarized slot antenna for ultrawideband (UWB) applications is proposed. The slot has an overall shape of a square ring whose four arms are identical and stepped rectangular. While two adjacent arms of the ring are microstrip-fed and are responsible for the orthogonally polarized fields, the other two arms are introduced to make the structure symmetric and reduce the cross polarization. The impedance matching and isolation are controlled by properly shaping the slot arms and the feed section and by insertion of narrow metallic and slot stubs. The measured impedance bandwidth is 120% (3.0-12.0 GHz). The isolation is better than 20 dB over most of the band. With the help of radiation patterns and aperture electric field distribution, the dual-polarized nature of the antenna is justified. The antenna will be useful for UWB multiple-input-multiple-output (MIMO) transmission, polarimetric radar, and medical imaging applications.

Design of a square ring shape slot antenna for UWB polarization–diversity applications

In this paper, a dual polarized slot antenna for ultra wideband applications is proposed. The slot has an overall shape of a square ring whose four arms are identical and stepped rectangular. While two adjacent arms of the ring are microstrip fed and are responsible for the orthogonally polarized fields, the other two arms are introduced to make the structure symmetric and reduce the cross polarization. The impedance matching and isolation are controlled by properly shaping the slot arms and the feed section and by insertion of several narrow metallic and slot stubs. The measured impedance bandwidth is 116% (from 3.2GHz to 12.0GHz) for both the ports. The isolation is better than 20dB from 4.4GHz onwards. With the help of radiation patterns and electric field distribution inside the slot, the dual polarized nature of the antenna is justified. A modified design having measured isolation of 18dB from 3.5GHz onwards is also presented. With compact features, huge impedance bandwidth, good isolation and acceptable cross polar levels along the boresight direction, the antenna is expected to be useful for UWB transmission incorporating MIMO, radar and medical imaging applications.

Design and Analysis of a Reflectarray Using Slot Antenna Elements for Ka-band SatCom

This paper presents a folded reflectarray designed for Ka-band satellite communication applications. The array element is a dual-polarized slot antenna with multilayered PCB structure and is designed to operate at 29.5–30.8 GHz band for both transmitting and receiving with single linear polarization. Vias are employed to suppress the surface wave propagation and reduce the mutual coupling between adjacent array elements, for achieving a reflectarray with a wide scan angle range. An equivalent circuit model for the array element is developed and it agrees well with the EM simulation results. Several passive demonstrators consisting of 116 elements spaced by $0.5{\lambda }_{30_{\rm{GHz}}}$ were fabricated and measured. The experimental results show that the presented reflectarray is capable of steering the beam up to $\pm 60^{\circ} $ in both E- and H-planes with low cross-polarization level.

Dual-Polarization Slot Antenna With High Cross-Polarization Discrimination for Indoor Small-Cell MIMO Systems

We demonstrate a dual-polarization slot antenna for indoor small-cell multiple-input–multiple-output (MIMO) systems. The symmetric structure and differential feeding promotes destructive interference of cross-polarized radiation in the far field to achieve high cross-polarization discrimination (XPD) in all directions. In addition, a very similar radiation pattern is observed not only between the major planes of each polarization but also between the two polarization orientations. Therefore, the proposed antenna can be considered as a stronger candidate for indoor small-cell MIMO systems. With an average XPD of 26.4 dB in all directions, the 3-D ray-tracing simulation results show a more than 22% increase in the system throughput compared to previous dual-polarization antennas for a single-user MIMO system in a typical indoor environment.

Dual frequency and dual circular polarization slot antenna for BeiDou navigation satellite system applications

ABSTRACTA new design of a dual frequency and dual circular polarization slot ring antenna for BeiDou Navigation Satellite System (BDS) applications is presented in this article. The dual frequency is achieved by two slot rings and the dual circular polarization is obtained by asymmetry slots adjacent to the rings. An antenna used for BDS applications with optimized parameters is designed, fabricated, and measured. Measured results show that the proposed antenna has good circular polarization for both right‐hand circular polarization and left‐hand circular polarization. The −10 dB return loss relative bandwidths for the lower and higher bands are about 4.4 and 12.0 %, respectively. The 3 dB axial ratio bandwidths are both about 5% with respect to the center frequencies of 1615.68 and 2491.75 MHz, respectively. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2222–2225, 2014

2-D Planar Scalable Dual-Polarized Series-Fed Slot Antenna Array Using Single Substrate

This communication proposes a dual-polarized slot antenna array, which is able to expand two-dimensionally (2-D), using only one layer of substrate board. Two identical coplanar waveguide (CPW) series-fed slot arrays are positioned orthogonally, providing dual polarization with high port isolation. The overall array is arranged on both sides of a single substrate, achieving low cost in fabrication. To validate the design concept, a model of the proposed array is built for the 2.4-GHz wireless local area network (WLAN) application. We have measured S parameters, radiation patterns and gain, and compared them with the simulation results.

A Wideband Dual-Polarized Slot Antenna

In this letter, we have proposed a dual-polarized planar circular slot antenna for wideband application. Two orthogonal polarizations were achieved by adopting different feeding mechanisms with high ports isolation. The horizontal polarization is excited by a meander-line coupled slot, and the vertical polarization is fed by a stepped monopole. The prototype of the proposed antenna has been built and tested. The proposed design obtained a fairly wide bandwidth (1.70-2.71 GHz) and a high isolation (> 33 dB) over the entire band. The gain of the dual polarizations is also measured and discussed.

A COMPACT OMNIDIRECTIONAL DUAL-POLARIZED ANTENNA FOR 2.4-GHZ WLAN APPLICATIONS WITH HIGHLY ISOLATED ORTHOGONAL SLOTS

An omnidirectional dual-polarized slot antenna with high port isolation for 2.4-GHz wireless local area network (WLAN) applications is proposed in this paper. The omnidirectional radiation patterns of the vertical polarization (VP) and horizontal polarization (HP) are achieved by individually cutting two orthogonal slots onto the metal walls of a cuboid antenna. The overall volume of the compact antenna is only 60 £ 10 £ 10mm 3 (0.488‚0 £ 0:081‚0 £ 0:081‚0). A prototype of the designed antenna is manufactured and tested. Both simulated and measured results show that the i10dB impedance bandwidths of dual polarizations cover the desired band of 2.4{ 2.484GHz and the port isolation, in the operating frequency, is less than i35dB. Stable measured gains are greater than 2.75 and 1.35dBi for the VP and HP, respectively.