Search

A two-element MIMO antenna, with improved isolation and pattern diversity, is designed and presented. The dual-band MIMO covers both the adjacent upper WLAN (5.2 GHz) and WiMAX (5.8 GHz) bands with clear isolation between them. The unit radiator of the MIMO is a co-planar waveguide-fed trapezoidal patch that achieves its resonant modes by adjusting the slope of the non-parallel sides. A frequency selective meta-structure is placed in-between the two radiating elements to reduce the mutual coupling and achieve pattern diversity. The MIMO offers peak gains of 1.56 and 5.16 dB at 5.2 GHz (5.1–5.34 GHz) and 5.8 GHz (5.68–5.9 GHz), respectively. The port-isolations achieved at WLAN and WiMAX bands are 26 and 23 dB, respectively. The correlation co-efficient (ECC < 0.05), diversity gain (DG > 9.99) and channel capacity loss (CCL < 0.03) also adhere to the criteria for MIMO operation. The measured results are in good agreement with the simulated ones. [ABSTRACT FROM AUTHOR]

A four-element multiple-input-multiple-output (MIMO) antenna has been designed to operate at triple wide bands with improved port-isolation and polarisation diversity. The resonant modes of the MIMO are achieved by meander slot-loaded elliptical-shaped fundamental radiators, and the inter-port isolation is achieved by employing neutralising line-embedded ground plane. Apart from port-isolation, the proposed MIMO also offers polarisation diversity at different operating bands. The triple-band MIMO offers linear polarised radiation at WLAN band (4.2–5.6 GHz), right-hand circular polarised (RHCP) radiation at C-band (6.3–7.5 GHz) and left-hand circular polarised (LHCP) radiation at X-band (8.7–9.3 GHz). The overall isolation (>27 dB), envelope correlation co-efficient (ECC<0.0005), diversity gain (DG>9.9995), mean effective gain (MEG<0.734 dB), total active reflection co-efficient (TARC<−20 dB) and channel capacity loss (CCL<0.35 bits/S/Hz) meet the criteria for reliable MIMO operation. The proposed MIMO has been fabricated on a 55.6 × 55.6 × 1.6 mm3 piece of an FR-4 epoxy substrate after simulation and measured in VNA. Adequate similarity can be observed between the measured and simulated results. [ABSTRACT FROM AUTHOR]

In this article, modified Koch fractal geometry-based patch antenna up to second iteration is implemented with partial ground configuration to achieve multiband response with wideband behavior at each of the resonating bands. The antenna is designed to operate over C and X bands that can be useful for Satellite, Radar and DBS TV applications. FR-4 epoxy substrate of maximum dimension 35 × 30 × 1.6 mm³ (0.70λ0 λ 0.6λ0 λ 0.03λ0) is used to simulate the antenna in HFSS 15 (λ0 is the free space wavelength corresponding to the lowest resonance frequency). The design is started with a truncated star shape patch and ended up with five circular slots embedded Koch fractal through several design steps. In addition, coplanar waveguide (CPW) feeding is applied to achieve multiband response and wideband behavior over each operating band. The proposed antenna exhibits multiband response at 6.06 GHz, 9.76 GHz, 10.92 GHz, 11.68 GHz and 14.4 GHz with operating bands (5.8–6.31 GHz), (9.2–10.08 GHz), (10.78–12.36 GHz) and (13.64–15 GHz) respectively. A fabricated prototype of the proposed antenna is tested using Vector Network Analyzer (VNA). It has shown adequate amount of matching between the simulation and measured results. [ABSTRACT FROM AUTHOR]

A compact frequency band reconfigurable dual-mode antenna utilizing both Koch fractal geometry and circular complementary split ring resonators (CSRRs) is presented in this paper. The proposed antenna can be electrically switched into both dual- and single-band resonance modes. A Koch curve derivative novel fractal curve is used to design the patch boundary of the antenna. Two optimized circular CSRRs are loaded inside the antenna geometry to achieve double-band resonance. The antenna operates at both 5.1 GHz (upper WLAN band) and 9.6 GHz (X -band) in dual resonance mode and resonates only at 8 GHz (X -band) in single resonance mode. A properly biased RF-range PIN diode placed at the slotted ground plane reconfigures the antenna in two operating modes by switching into its ON–OFF states. The antenna is fabricated on cost-efficient epoxy (FR-4) substrate consuming the maximum dimension of 0. 3 4 λ × 0. 3 2 λ which is much more compact than the conventional rectangular patch antennas designed for similar bands. Stable radiation characteristics with reduced cross-polarization are achieved at all the resonant bands of the antenna. A prototype of the proposed antenna is fabricated and measured. The simulated results are in good agreement with the measured ones. [ABSTRACT FROM AUTHOR]

Metamaterial properties of a novel half-mode CRLH unit cell are investigated and hence a compact dual-wideband antenna is designed using an array of four unit cells. The negative refraction of the metamaterial cell is utilized to miniature the antenna. A via-free open stub, in combination with an interdigital capacitor, makes the half-mode CRLH unit cell. The proposed antenna operates at both C-band (6.2–6.8 GHz) and X-band (8.5–9.2 GHz). The dual-wideband antenna is enabled with frequency reconfigurability by incorporating RF PIN diode in its ground plane in the next design step. The ON–OFF conditions of the PIN diode electrically switch the antenna into dual-band and single-band modes, respectively. In OFF state of the diode, the antenna behaves as a monopole and operates in single-band mode resonating at C-band (5.9–6.5 GHz) only. The measured results of the fabricated sample are in good agreement with the simulated ones. [ABSTRACT FROM AUTHOR]