Query: SLOT ANTENNA

title: Eight Element Dual Polarized MIMO Slot Antenna System for 5G Smartphone Applications
abstract: In this paper, we propose an eight port/four resonator slot antenna array with a dual polarized function for multiple input multiple output (MIMO) 5G mobile terminals. The design is composed of four dual polarized square ring slot radiators fed by pairs of microstrip line structures. The radiation elements are designed to operate at 3.6 GHz and are located on the corners of the smartphone PCB. The square ring slot radiators provide good dual polarization characteristic with similar performances in terms of fundamental radiation characteristics. In order to improve the isolation and also reduce the mutual coupling characteristic between the adjunct microstrip line feeding ports of the dual polarized radiators, a pair of circular ring/open ended parasitic structures is embedded across each square ring slot radiator. The 10 dB impedance bandwidth of each antenna element is 3.4 3.8 GHz. However, for 6 dB impedance bandwidth, this value is 600 MHz (3.3 3.9 GHz) The proposed MIMO antenna offers good S parameters, high gain radiation patterns, and sufficient total efficiencies, even though it is arranged on a high loss FR 4 dielectric. The SAR function and the radiation characteristics of the proposed design in the vicinity of user hand/user head are studied. A prototype of the proposed smartphone antenna is fabricated, and good measurements are provided. The antenna provides good features with a potential application for use in the 5G mobile terminals.

title: A multiband reconfigurable slot antenna for wireless applications
abstract: This research presents a novel four band frequency reconfigurable antenna for 1.6 (Global Navigation Satellite system (GNSS) 2.5 (Lower Worldwide Interoperability for Microwave Access (WiMAX) 5.8 (Wireless local area network (WLAN) and 9.8 GHz (X band) frequency bands. The antenna has a compact size of 0 18 l 0 x 0.18 l 0 x 0.0096 l 0 at lower resonance of 1.8 GHz and is printed on FR4 material with height (h) 1.6 mm, dielectric constant e r 4.4 and loss tangent d 0.02. Multiband phenomenon in the antenna is achieved by etching trapezoidal slot in the radiating monopole and rectangular slots in the ground plane. Frequency reconfiguration in the proposed structure is achieved by placing PIN diode switch between rectangular slot placed in the ground plane. During OFF state, the antenna exhibit quad band with S11

title: Miniaturized Circularly Polarized Square Slot Antenna With Enhanced Axial Ratio Bandwidth Using an Antipodal Y strip
abstract: A novel single fed, wideband, circularly polarized slot antenna is proposed and fabricated. Wideband circular polarization is obtained by introducing an antipodal Y strip to a square slot antenna. The feedline is a U shaped microstrip line that provides a wide impedance bandwidth. The overall size of the antenna is only <inline formula> <tex math notation="LaTeX"\text{28} \times \text{28} \text{mm}{2} \text{0.3} \lambda _{o} \times \text{0.3} \lambda _{o}/tex math>/inline formula> A prototype of the antenna is fabricated and tested. The measured bandwidths for the axial ratio <inline formula><tex math notation="LaTeX"\text{AR} \text{3} \text{dB}/tex math>/inline formula> and relative impedance <inline formula><tex math notation="LaTeX" {S_{11} \text{10} \text{dB}/tex math>/inline formula> are 41.3% (from 4.4 to 6.67 GHz) and 84% (from 3.25 to 8 GHz) respectively, and the antenna has a stable radiation pattern and a gain of greater than 3 dBi over the entire circular polarization frequency band.

title: A miniaturized metamaterial slot antenna for wireless applications
abstract: A novel miniaturized five band metamaterial inspired slot antenna is reported. The proposed design consists of a ring monopole and metamaterial Rectangular Complementary Split Ring Resonator (RCSRR) as the radiating part, two L and one T shaped slot as the ground plane, respectively. Miniaturization in the proposed design is accomplished by metamaterial RCSRR, and also, it helps the antenna to operate at 2.9 and 5.2 GHz frequency bands. The aforementioned miniaturization process leads to about 46.8% reduction in volume of the proposed design, as compared to the conventional antenna. The pass band characteristics of the metamaterial RCSRR through waveguide medium are discussed in detail. In order to enhance the operating abilities of the miniaturized antenna, slots are etched out in the ground plane, thereby making the miniaturized antenna further operate at 2.4, 5.6 and 8.8 GHz, respectively. The proposed design has an active patch area of only with dB bandwidth of about 4.16% (2.35 2.45 GHz) 5.71% (2.63 2.76 GHz) 10.25% (4.44 4.92 GHz) 6.25% (5.42 5.77 GHz) and 2.39% (8.68 8.89 GHz) in simulation, and about 6.86% (2.25 2.41 GHz) 5.01% (2.55 2.7 GHz) 9.16% (4.58 5.02 GHz) 5.38% (5.79 6.11 GHz) and 5.42% (8.44 8.91 GHz) in measurement. The antenna has good impedance matching, acceptable gain and stable radiation characteristics across the operational bandwidths.

title: A Novel Reconfigurable Metal Rim Integrated Open Slot Antenna for Octa Band Smartphone Applications
abstract: In this paper, a novel reconfigurable open slot antenna has been proposed for LTE smartphone applications to cover a wide bandwidth of 698 960 and 1710 2690 MHz. The antenna is located at the bottom portion of the mobile phone and is integrated with metal rim, thereby occupying a small space and providing mechanical stability to the mobile phone. Varactor diode is used to cover the lower band frequencies, so as to achieve a good frequency coverage and antenna miniaturization. The operational principles of the antenna are studied and the final design is optimized, fabricated, and tested. It has achieved the desired impedance bandwidth and the total efficiency of minimum 50% in free space throughout the required bands. The antenna performance with mobile phone components and human hand is also been studied. Furthermore, the SAR in a human head is investigated and is found to be within allowable SAR limits. Finally a multiple input multiple output antenna configuration with high isolation is proposed; it has an identical reconfigurable open slot antenna integrated at the top edge of the mobile phone acting as the secondary antenna for 698 960 and 1710 2690 MHz. Thus the proposed antenna is an excellent candidate for LTE smartphones and mobile devices.

title: Design and Fabrication of a High Gain 60 GHz Cavity Backed Slot Antenna Array Fed by Inverted Microstrip Gap Waveguide
abstract: This communication deals with the design of a <inline formula> <tex math notation="LaTeX"$16\times 16$ /tex math>/inline formula> slot array antenna fed by inverted microstrip gap waveguide (IMGW) The whole structure designed in this communication consists of radiating slots, a groove gap cavity layer, a distribution feeding network, and a transition from standard WR 15 waveguide to the IMGW. First, a <inline formula> <tex math notation="LaTeX"$2\times 2$ /tex math>/inline formula> cavity backed slot subarray is designed with periodic boundary condition to achieve good performances of radiation pattern and directivity. Then, a complete IMGW feeding network with a transition from WR 15 rectangular waveguide to the IMGW has been realized to excite the radiating slots. The complete antenna array is designed at 60 GHz frequency band and fabricated using Electrical Discharging Machining Technology. The measurements show that the antenna has a 16.95% bandwidth covering 54 64 GHz frequency range. The measured gain of the antenna is more than 28 dBi with the efficiency higher than 40% covering 54 64 GHz frequency range.

title: Design and Fabrication of a High Gain 60 GHz Corrugated Slot Antenna Array With Ridge Gap Waveguide Distribution Layer
abstract: A wideband high gain high efficiency 16 x 16 element slot antenna array is presented for 60 GHz band applications. The antenna is designed based on gap waveguide technology. The most important advantage of using this technology is its ability to decrease complexity and cost of fabrication because there is no requirement of electrical contact between the three layers of the antenna structure. The three layers are a corrugated metal plate with radiating slots, a subarray cavity layer, and a ridge gap waveguide (RGW) feed network layer. The corporate feed network is realized by a texture of pins and guiding ridges in a metal plate. Also, in order to excite the antenna with a standard V band rectangular waveguide, a transition from RGW to WR 15 is designed. The radiating elements, corrugations, cavity layer, power dividers, and transition are designed and optimized to suppress the reflection coefficient at the input WR 15 port over the desired frequency range from 57 to 66 GHz. Finally, the 16 x 16 element slot antenna array is fabricated by the standard milling technology. The measured results demonstrate about 16% of reflection coefficient bandwidth |S11| 10 dB) covering the 56 65.7 GHz frequency range, and the measured gain is larger than 32.5 dBi over the band with more than 70% antenna efficiency.

title: A Novel Simple and Compact Microstrip Fed Circularly Polarized Wide Slot Antenna With Wide Axial Ratio Bandwidth for C Band Applications
abstract: This communication presents a design of a new compact circularly polarized (CP) slot antenna fed by a microstrip feedline. The 3 dB axial ratio band can be achieved by simply protruding a horizontal stub from the ground plane toward the center of the wide slot (WS) and then feeding the WS with a microstrip feedline positioned to the side of the WS, underneath the protruded stub. The feedline and metallic stub are perpendicular to each other, and they resemble a T shape when viewed from the top. The proposed antenna is fabricated with an area of 25 x 25 mm2. Measurement results show that the antenna attains an S11 10 dB impedance matching bandwidth of 90.2% from 3.5 to 9.25 GHz, and a broadband 3 dB AR bandwidth of 40% ranging from 4.6 to 6.9 GHz. A peak gain of 0.8 4.5 dBi is achieved within the AR band. The proposed antenna is suitable for circular polarization applications in C band.

title: Compact MIMO Slot Antenna for UWB Applications
abstract: A compact four element multiple input multiple output (MIMO) antenna for portable wireless ultrawideband (UWB) applications is presented in this letter. The proposed UWB MIMO antenna has the compact size of 42 x25 mm2. The microstrip fed stepped slot antenna acts as a single UWB antenna element. The UWB antenna covers the wide frequency band from 3.1 to 12 GHz. High isolation 22 dB) is achieved between the UWB antenna elements without any decoupling network. It is due to inherent directional radiation properties of slot antennas (SAs) and their asymmetrical placements. The measured impedance bandwidth of UWB MIMO antenna is from 3.2 to 12 GHz with the isolation better than 22 dB over the entire UWB spectrum. The envelope correlation coefficient (ECC) as well as channel capacity loss (CCL) are investigated, and they are within their acceptable limits.

title: Polarization conversion of metasurface for the application of wide band low profile circular polarization slot antenna
abstract: In this letter, based on a corner cut square metasurface, a planar polarization conversion structure is presented and the application for wide band low profile circular polarization (CP) slot antenna is proposed. The mechanisms for achieving the CP state from a linearly polarized incident wave and for broadening the working bandwidth of conventional slot antenna are analyzed theoretically. The wide band low profile CP slot antenna is achieved with numerical optimizations and parameter studies. Both simulations and measurements are performed to demonstrate the proposed antenna, and good agreements are obtained. Such results will open the path for polarization conversion metasurfaces used in the CP antenna area.