Circular Polarization Dielectric Resonator Antenna Excited by Single Loop Feed

A new feeding method for the circular polarization (CP) dielectric resonator antenna (DRA) is proposed in this letter. Two orthogonal modes (TE^x_δ11, TE^y_1δ1,) of the rectangular DRA are excited by a 90° phase difference of the differential and common modes currents of the proposed feeding structure. To demonstrate the good CP performance of the proposed method, a right‐hand CP DRA for a global positioning system was designed. The impedance bandwidth of the proposed antenna for S₁₁相似文献   

A wideband high gain dielectric resonator antenna for RF energy harvesting application

A novel high gain and broadband hybrid dielectric resonator antenna (DRA) is designed and experimentally validated. To obtain the wide impedance bandwidth, the proposed antenna geometry combines the dielectric resonator antenna and an underlying slot with a narrow rectangular notch, which effectively broadens the impedance bandwidth by merging the resonances of the slot and DRA. An inverted T-shaped feed line is used to excite both antennas, simultaneously. It supports amalgamation of different resonant modes of the both, DRA and slot antenna. The measured results show that the proposed antenna offers an impedance bandwidth of 120% from 1.67 to 6.7 GHz. The antenna gain is next enhanced by a reflector placed below the antenna at an optimum distance. On engineering the height and dimension of this reflector the antenna gain is improved from 2.2 dBi to 8.7 dBi at 1.7 GHz. Finally, antenna operation is attested experimentally with a rectifier circuit in the frequency range of 1.8–3.6 GHz, where various strong radio signals are freely available for RF energy harvesting. The measured maximum efficiency of the rectifier and rectenna circuit were found to be 74.4% and 61.4%, respectively.     

Improvement of the Performance Characteristic of UWB Antenna Using a Novel Double-Layer FSSs Operating at the Ku-Band

This paper proposed a novel compact design of UWB antenna. Our design used an uni-planar EBG double-layer of FSSs to enhance performance characteristics of UWB antenna in operation frequency of 14 GHz/Ku Band. This UWB antenna occupies a compact size of 40.36?×?29.36 mm² with space/gap between the radiator patch and double-layer of FSSs is 10 mm. We used a simple rectangular truncated-corner as a radiating patch. Double-layer of FSSs consist of a lower layer of FSS that used a unit cell of rectangular loop and an upper layer of FSS applied a wire grid. Optimized size of the truncated-corner is 2?×?0.5 mm², optimal space/gap between radiator patch and double-layer of FSSs is 10 mm, and the width of a rectangular loop in the lower layer of FSS is 1.742 mm. Our proposed uni-planar EBG double-layer of FSSs based UWB antenna reaches S11 parameter of ?42.381, a ?10 dB impedance bandwidth of 1.941 GHz (12.964–14.905 GHz), and a VSWR of 1.0154 in operation frequency 14 GHz. In addition, our UWB antenna design has a high gain about 6.1 dB. Applying of uni-planar EBG double-layer of FSSs improve significantly the performance characteristic of UWB antenna.

     

Circularly Polarized SIW DRA Fed by Ridge Gap Waveguide for 60 GHz Communications

Wireless Personal Communications - A compact planar dielectric resonator antenna (DRA) is designed based on the substrate integrated waveguide (SIW) technology for 60 GHz communications....     

Ultra-Wideband Compact Circularly Polarized Antenna

In this research work, a circularly polarized (CP) monopole antenna is designed for Ultra-Wideband (UWB) applications. The CP UWB antenna is be made up of a reformed ring patch and ground plane. The slots and stubs are inserted in the ground to achieve CP in the UWB antenna. This antenna attained an Axial Ratio Bandwidth (ARBW) of 5 GHz (4.0–9.0 GHz) that lies in the UWB frequency range that is from 3.1 to 10.6 GHz. The designed antenna has a radiation efficiency of around 80% for the complete UWB frequency range. The CP UWB antenna is designed and fabricated using the FR4 with a compact size of 32?×?30?×?1.6 mm³ and with a peak gain of 6.8 dBi. Tested results are in good resembles with simulated ones.

     

Cross-T-shaped dielectric resonator antenna for wideband applications

A new dielectric resonator antenna (DRA) is introduced for wideband applications, where the wideband of this DRA design comes from three factors: a compact cross-T-shaped dielectric resonator, a conformal inverted-trapezoid patch as a feed mechanism, and a copper-clad substrate as a baseboard. Measured results demonstrate that the proposed DRA achieves an impedance bandwidth of about 71.8% for VSWR les 2, covering a frequency range from 3.56 to 7.57 GHz. This antenna also provides a stable broadside radiation pattern and a gain range of 3.2-7.3 dBi across the operating bandwidth.     

A Coalesced Kite Shaped Monopole Antenna for UWB Technology

A small and compact monopole antenna of dimensions 25?×?18?×?1.6 mm³ is presented for UWB communications. The proposed design consists of two kite shaped radiators in coalesced form and a tapered slotted ground plane for the UWB characteristics. The parametric study of the patch and the modified ground plane is made and the measured impedance bandwidth of 14.2 GHz (2.8–17 GHz) is achieved. The measured antenna gain varies from 2.28 to 5.0 dBi for the entire frequency band of application. Group delay, signal analysis and antenna isolation |S₂₁| are also studied at different orientations of the antenna and found to be quite satisfactory to meet the requirements for UWB applications. The co- and cross-polarization patterns are also calculated for E and H-planes, and compared with the measured results. Antenna simulation and optimization are performed using CST Microwave Studio and design is fabricated and measured for the validation of the results.

     

Compact body-worn MIMO antenna with high port isolation for UWB applications

This article investigates the mutual coupling reduction of a compact two elements wearable ultra-wideband (UWB) multiple-input multiple-output (MIMO) antenna. The ground plane of the proposed wearable MIMO antenna structure consists of three connected square ring-shaped stubs and two rectangular slots of narrow height. These ground stubs and slots minimize the mutual coupling effect between antennas and provide high isolation. The suggested MIMO antenna functions from the 1.87 to 13.82 GHz frequency spectrum covering WLAN (2.4–2.484 GHz), UWB (3.1–10.6 GHz), and X band (8–12 GHz) with 152.32% fractional bandwidth. It sustains port isolation above 27 dB throughout the 2 to 13.82 GHz frequency band. Inside the whole working frequency band, the suggested antenna offers a tiny envelope correlation coefficient (ECC < 0.098), greater diversity gain (DG > 9.93 dB), minimum channel capacity loss (CCL < 0.32 bits/s/Hz), and slight magnitude variation in mean effective gain of antenna ports (< 0.1 dB). The recommended antenna yields a SAR level below the designated threshold (<1.6 W/kg), affirming its suitability for body-worn applications. The designed MIMO antenna structure has an overall volume of 32 × 48 × 1.5 mm³.     

Theoretical and Experimental Investigation of a Ka-band Gyro-TWT with Lossy Interaction Structure

The stability analysis of a Ka-band gyrotron traveling-wave tube amplifier (gyro-TWT) operating in the circular TE₀₁ mode at the fundamental cyclotron harmonic is presented. The small signal linear theory is used to analyze the amplification of operation mode and oscillation of parasitic modes. The optimum dielectric parameters including loss layer thickness and permittivity are given. Propagation loss of operation mode is 3 dB/cm with the thickness of loss layer d = 0.7 mm and relative permittivity ξ″ = 11−6j, and propagation loss per unit length of parasitic modes TE₁₁, TE₂₁, TE₀₂ at each oscillation frequency (24.85 GHz, 27.85 GHz, 61.2 GHz) is 2.5 dB/cm, 6 dB/cm, 7.5 dB/cm, respectively, sufficient to suppress oscillations of operation and parasitic modes. Taking advantage of the optimized parameters of loaded dielectric, a high gain scheme has been demonstrated in a 34-GHz, TE₀₁-mode gyro-TWT, producing 160 kW saturated output power at 40 dB stable gain and 22.8% efficiency with a 3-dB bandwidth of 5%.     

Compact UWB monopole antenna with quadruple band notched characteristics

ABSTRACT

A compact planar Ultrawideband (UWB) monopole antenna with quadruple band notch characteristics is proposed. The proposed antenna consists of a notched rectangular radiating patch with a 50 Ω microstrip feed line, and a defected ground plane. The quadruple band notched functions are achieved by utilising two inverted U-shaped slots, a symmetrical split ring resonator pair (SSRRP) and a via hole. The fabricated antenna has a compact size of 24 mm × 30 mm × 1.6 mm with an impedance bandwidth ranging from 2.86 to 12.2 GHz for magnitude of S₁₁ < ?10 dB. The four band notched characteristics of proposed antenna are in the WiMAX (worldwide interoperability for microwave access) band (3.25–3.55 GHz), C band (3.7–4.2 GHz), WLAN (wireless local area network) band (5.2–5.9 GHz) and the downlink frequency band of X band (7–7.8 GHz) for satellite communication are obtained. The measured and simulation results of proposed antenna are in good agreement to achieve impedance matching, stable radiation patterns, constant gain and group delay over the operating bandwidth.     

Wheel shaped modified fractal antenna realization for wireless communications

A compact, low profile circular fractal patch antenna with low latency, low cost, high speed and multiband is presented. With the help of CST Microwave Studio Suite TM the proposed structure has been designed and analyzed. The simulated results are fixed experimentally. The suggested antenna has dimension of 32 × 36 mm² (W × L) and operating from 2.93 GHz–9.53 GHz with VSWR ≤ 2. The aerial is assembled on FR-4 (ε_r = 4.4) substrate with a thickness of substrate 1.25 mm. Detailed parametric studies of the antennas have been carried out. This microstrip fed antenna is suitable for ultra wideband (UWB), S, C and part of the X band applications.     

Two-Element Quad-Band MIMO Antenna Employing Meandered Arm Printed Inverted–F Antenna

This article proposed a compact dual-element MIMO (multiple-input-multiple-output) antenna system working in 1.575 GHz (Global Positioning System)/4.5 GHz (5G)/5.8 GHz (Wireless Local Area Network)/6.4 GHz (Satellite communication) with relatively high isolation. The proposed antenna element consists of compact inverted-F antenna with meandered arm. One side of the T-shaped monopole antenna is extended and meandered while the other side is grounded to form the IFA structure. Meandering of the arm is responsible for the quad-band response. The proposed structure is simulated and fabricated on a FR4 substrate with an overall dimension of (0.23 λ₀?×?0.09 λ₀?×?0.004 λ₀) and edge-to-edge separation of the two patches is 0.04 λ₀, where λ₀ is the wavelength at lower resonating frequency (1.575 GHz) of the proposed antenna. The high isolation is achieved by incorporating two inverted L-shaped strips and a narrow slot in the ground plane. Envelope correlation co-efficient (ECC) and channel capacity loss (CCL) are within their acceptable limits. Other different diversity parameters are evaluated and the results are satisfactory for MIMO applications.

     

High Gain Compact Multiband Cavity-Backed SIW and Metamaterial Unit Cells with CPW Feed Antenna for S,and Ku Band Applications

A compact multiband cavity-backed substrate integrated waveguide (SIW) and metamaterial antenna with coplanar waveguide (CPW) feed is designed for S and K_u bands thereby providing low and high frequency applications. Designing simultaneous achievement of high gain in S band and K_u band antennas are challenging task, but the proposed antenna overcomes this limitation. The proposed antenna has a ground structure with radiating T-shaped stub opposite to the feed line and a combination of SIW and metamaterial. SIW and complementary square split ring resonator (CSSRR) are used to enhance efficiency, directivity, gain and bandwidth. The proposed antenna structure uses FR-4 epoxy as the substrate material with ?_r?=?4.4 with a dimension of 40 × 40?×?1.6 mm and analyzed using ANSYS HFSS. The designed antenna resonates at three frequencies (i.e.), 4.23, 13.63 and 17.05 GHz with a gain greater than 5 dBi and efficiency greater than 80%. It is suitable for S band (ISM, WLAN, WiMax) and K_u band (radar, satellite communications) applications. The designed antenna is linearly polarized with high gain and efficiency at both the bands.

     

Low profile equilateral-triangular dielectric resonator antenna ofvery high permittivity

An aperture-coupled equilateral-triangular dielectric resonator antenna (DRA) of very high permittivity (ϵ_r=82) is investigated experimentally. The triangular DRA is more compact in size than rectangular and circular disk DRAs operating at the same frequency. The impedance matching, radiation patterns and antenna gain of the triangular DRA are presented     

A printed monopole ellipzoidal UWB antenna with four band rejection characteristics

An antenna design with four band rejection characteristics for UWB application is demonstrated. The proposed unique UWB antenna has shape of an embedded ellipse at top of trapezoidal patch (named as ellipzoidal), 50 Ω impedance microstrip line feed and a truncated beveled ground plane. To realize four band stop characteristics, three inverted U-shaped and a single I-shaped slots each of half guided wavelength are utilized on radiating element. The fabricated antenna has dimensions of 27 mm × 36 mm × 1.6 mm. This four band notched ellipzoidal UWB antenna has measured frequency bandwidth 2.8–14 GHz for magnitude of S₁₁ < −10 dB level. The measured ellipzoidal antenna exhibits four band rejection characteristics for magnitude of S₁₁ > −10 dB at 3.55 GHz for WiMAX band (3.26–3.9 GHz), 4.55 GHz for ARN band (4.35–5.05 GHz), 5.7 GHz for WLAN band (5.5–6.65 GHz) and 8.8 GHz for ITU-8 band (7.95–9.35 GHz). The proposed ellipzoidal UWB antenna maintains omnidirectional radiation pattern, gain, linear phase response, <1 ns group delay, and transfer function in the whole UWB operating bandwidth except at notched frequency bands.     

A Dual-Band Circularly Polarized Hexagonal Ring Antenna for Handheld RFID Readers

In this paper, a compact, lightweight, low-profile dual-band circularly polarized antenna is presented for handheld radio frequency identification (RFID) readers. The proposed antenna consists of two concentric hexagonal rings and a feed network printed on different layers of the dielectric substrate. The antenna configuration exploits a stacked-coupled technique for gain enhancement and single-port feeding for easy manufacturing. The center frequencies of the two resonating bands are 0.92 GHz (UHF) and 2.45 GHz (ISM). The antenna exhibits circular polarization characteristics in both the resonating bands, therefore encountering the losses due to polarization mismatch and increasing the tag detection reliability. A prototype of the proposed RFID antenna is simulated and fabricated, and experimental results are in close agreement. The peak antenna gain is 3.3 dB and 5 dB in the UHF and ISM bands, respectively. The overall size of the RFID antenna is 80 mm?×?80 mm?×?7.76 mm.

     

Miniaturized active stepped impedance planar inverted-F antenna using common ground

This paper presents a compact active integrated antenna (AIA) comprising of class-A power amplifier (PA) and stepped impedance planar inverted-F antenna (PIFA). In the proposed design, a common ground is used for both PA and PIFA, resulting a compact antenna of size 0.14λ₀ × 0.11λ₀ × 0.01λ₀ (λ₀ is free space wavelength at 0.85 GHz). Moreover, it is demonstrated that by using the stepped impedance radiator the operating frequency of the active PIFA is shifted down from its natural resonant frequency of 1.36 GHz to 0.85 GHz, offering an extensive size reduction of 80%. This active integration increases the passive antenna gain through the effective loading of the antenna to the power amplifier. The measured result indicates that the active and passive antennas achieved the gain of 15.7 dB and 3.81 dBi, respectively after the integration. In addition, the maximum SAR value of antenna is found to be 0.64 W/kg.     

Compact UWB Antenna with High Rejection Triple Band-Notch Characteristics for Wireless Applications

In this paper, small printed flower-shape triple notch ultra-wideband (UWB) monopole antenna with high band rejection is presented. Notch bands include WiMAX (IEEE802.16 3.30–3.80 GHz), WLAN IEEE802.11a/h/j/n (5.15–5.35, 5.25–5.35, 5.47–5.725, 5.725–5.825 GHz), and X-band downlink satellite system (7.1–7.9 GHz). By including inverted T-shape stub and etching two C-shaped slots on the radiating patch, triple band-notch function is obtained with measured high band rejection (VSWR = 14.52 at 3.58 GHz, VSWR = 15.88 at 5.69 GHz and VSWR = 6.95 at 7.61 GHz) and covers a UWB useable fractional bandwidth of 114.30% (2.74–10.57 GHz = 7.83 GHz). In short the antenna offers triple band-notch UWB systems as a compact multifunctional antenna to reduce the number of antennas installed in wireless devices for accessing multiple wireless networks with wide radiation pattern. The proposed antenna has a small size of about 0.25λ × 0.30λ at 4.2 GHz (first resonance frequency), which has a size reduction of 30% with respect to the earlier published antenna. Both the experimental and simulated results of the proposed antenna are presented, indicating that the antenna is a good candidate for various UWB applications.

     

Performance Analysis of a Low Profile Hybrid Antenna for Broadband Applications

In this paper, a low profile dielectric resonator antenna (DRA) is proposed and investigated. To achieve the broad impedance bandwidth the proposed antenna geometry combines the dielectric resonator antenna and an underlying microstrip-fed slot with a narrow rectangular notch, which effectively broadens the impedance bandwidth by merging the resonances of slot and DRA. The physical insight gained by the detailed parametric study has led to find out a set of guidelines for designing the antennas for any particular frequency band. The design guidelines have been verified by simulating a set of antennas designed for different frequency bands. For validation, a prototype antenna is fabricated and tested experimentally. The measured results show that the proposed DRA offers an impedance bandwidth of about \(125.34\%\) from 1.17 to 5.1 GHz with reasonable gain between 3.5 and 5.7 dBi. The volume of the proposed DRA is \(0.16\lambda _{dr}^{3}\), where \(\lambda _{dr}\) is the wavelength at center operating frequency of the DR. A comprehensive study on bandwidth shows that the proposed DRA provides maximum bandwidth in terms of the DR volume (\(\hbox {BW}/V_{dr}\)) and the DR height (\(\hbox {BW}/h_{dr}\)) than the other similar reported work on hybrid wideband DRA designs.     

Novel Utilization of the Dielectric Resonator Antenna as an Oscillator Load

For the first time, the idea of using the dielectric resonator antenna (DRA) as an oscillator load, named as DRAO, is presented in this paper. Unlike the conventional dielectric resonator oscillator (DRO), where the DR was merely used as a resonator, the DR here serves as both the radiating and oscillating loads. In addition, a compact tri-function hollow DR that incorporates the packaging function to the above dual function is demonstrated. The design procedures of the dual- and tri-function DRAOs are discussed. For demonstration, the DRAOs are designed at 1.85 GHz, which is used in the popular personal communications system (PCS). The return losses, input impedances, antenna gains, signal spectrums, phase noise, and radiation patterns of the two DRAOs are presented. It is shown that the loaded Q_L factor of the DRA can be increased by internally embedding a compact metallic cavity to the DR. It is found that with a higher loaded Q_L factor, the phase noise of the antenna oscillator using the hollow DRA (tri-function DRAO) is better than that using a solid DRA (dual-function DRAO).