Semi-elliptical Patch Research Articles

High gain antenna for n260- & n261-bands and augmentation in bandwidth for mm-wave range by patch current diversions

PurposeA compact low-cost antenna structure is proposed to augment the impedance-bandwidth in mm-wave range. Beside it, the paper also aimed to enhance high gain for n260 and n261-bands, suitable for futuristic communication systems.Design/methodology/approachDesign consists of radiating patch and a partial ground plane with semi-circle arc for smooth flow of current. The lower corners of patch are gradually clipped away to make the patch nearly elliptical. Further, two tilted slots at an angle α = 15° are etched at the edges of the patch to augment bandwidth for mm-wave range. These slots divert the periphery current of semi elliptical patch towards center portion of antenna which ensures the participation in radiation of central portion of patch. The upper corners are also clipped away to limit the copper losses and smoothly flow of current. The proposed antenna is designed using HFSS and it is structured on inexpensive FR4 substrate of size 27.5 × 20 mm2.FindingsIt supports enormous −10 dB bandwidth of 5.86–40GHz (148.89%) even though use of high loss-tangent material and high gain for 28 GHz (27.50–28.35 GHz) n261–band and 37 GHz (37–38.6 GHz) and 39 GHz (38.6–40GHz) n260–bands with a peak-gain of 8.76 dBi, 10.8 dBi and 9.92 dBi, respectively.Originality/valueThe proposed methodology of design is very useful to enhance impedance bandwidth to cover all C–, X–, Ku–, K– and Ka–band even though use of low cost material with high loss tangent. In recent literature, the designs were implemented with a costly material and having very low loss tangent and covers partial suggest bands.

PLANAR UWB MIMO-DIVERSITY ANTENNA WITH DUAL NOTCH CHARACTERISTICS

This paper introduces a novel MIMO UWB antenna with dual notches. The proposedantenna is based on Quasi Self Complementary (QSC) method to give wide impedance bandwidthfrom 2.4GHz to more than 12 GHz. The proposed antenna consists of a semi-elliptical patch that isfed by a tapered microstrip line. The antenna is designed on an FR-4 substrate with compact size20mm × 15mm × 1.5mm. The dual notched bands are achieved by using a square ring printed on thebottom of the substrate to reject WiMAX at 3.6 GHz. Also, a C-shaped slot is etched in the radiatingpatch to reject interference with the WLAN band at 5.8 GHz. In the proposed MIMO antenna, theisolation reduction is achieved utilizing diversity technique to minimize the mutual coupling betweenthe antennas. The isolation between MIMO elements is more than 20 dB. The envelope correlationcoefficient (ECC), diversity gain (DG), total active reflection coefficient (TARC), furthermore, channelcapacity loss (CCL) are measured and calculated. The proposed antenna is designed, simulated, andmeasured. A good agreement is shown between the experimental and simulated results.

Hex-Sided Rounded Dipole Antenna (HSRDA) For UWB Applications

AbstractA hex-sided rounded dipole antenna (HSRDA) for UWB applications is presented. It is designed by the addition of semi-elliptical patch sections at the edges of a square bow-tie antenna. The antenna structure is fed by a modified microstrip feedline for better impedance matching. An impedance bandwidth of 2.9–11.4 GHz is achieved. The antenna structure has quasi omnidirectional radiation patterns and reasonable gain over the same frequency range. A good agreement between the experimental and simulation results is observed. The proposed antenna structure has miniaturized size for the same bandwidth as compared to already reported antenna structures.

Elliptical and circular bonded composite repair under mechanical and thermal loading in aircraft structures

In this study, the three-dimensional finite element method is used to achieve a comparison between the semi circular and semi elliptical patch repairs in aircraft structures. The comparison was done by the analysis of : the mechanical and thermal stress intensity factors (SIF and TSIF) at the tip of repaired crack and the distribution of the adhesive stresses for the two patch shapes. The obtained results show that the semi circular shape of the patch presents lower stress intensity factor at the crack tip, which is beneficial for the fatigue life and lower adhesives stresses, which is beneficial for the repair durability. In addition the circular patch is subjected to less significant thermal residual stresses compared to the elliptical shapes.

Broadband Semielliptical Patch Antenna with Semicircular Ring Slot for WiMax Application

This paper reports the design and analysis of a semielliptical patch antenna modified by cutting semicircular ring slot in patch geometry and obtained results are discussed. The reported antenna is designed on a multilayered substrate material having two glass epoxy FR-4 substrates separated by a thin foam substrate having thickness 1.0 mm. The size of ground plane is 75 mm×75 mm, whereas the patch dimension along major and minor axes is 23.0 mm and 14.0 mm, respectively. The two modes corresponding to resonance frequencies 3.39 GHz and 3.73 GHz are excited to provide wide impedance bandwidth 21.1% with respect to central frequency with stable radiation patterns. The antenna shows circular polarization with axial ratio bandwidth 5.5% and minimum axial ratio value 1.65 dBi. The radiation patterns of proposed antenna are normal to the surface of patch and are almost identical in shape as required for practical applications. The proposed antenna covers entire median band of WiMax communication systems ranges from 3.40 GHz to 3.6 GHz.