Reconfigurable dual band microstrip patch antenna for software defined radio applications

In this paper, a reconfigurable microstrip patch antenna with RF pin diode switches is implemented for dual band of 2.4 GHz and 5.6 GHz Software Defined Radio (SDR) applications. For the dual band SDR system, the use of a single antenna with a wide bandwidth to cover both of the bands can be limiting for low power level signal applications due to wideband noise. A reconfigurable nested microstrip patch antenna is designed on a Rogers 5880 RT/DUROID substrate which is fed by a coaxial probe from the back side of the grounded substrate. RF switching circuitry involves four RF pin diodes at each side of the inner patch. The dual bands of 2.4 GHz and 5.6 GHz frequency operation can be simply obtained by switching the PIN diodes on and off. The antenna is well matched and achieves approximately 7 dBi simulated gain at both frequency bands. Simulation results show that the nested patch antenna is suitable for dual band SDR applications

Reconfigurable Antenna with Elevation and Azimuth Beam Switching

A reconfigurable microstrip antenna is proposed for low-cost adaptive beam-switching applications. A small patch-slot-ring structure is used as the radiating element where an asymmetrical arrangement of p-i-n diodes is employed to switch the pattern in four directions. The antenna provides pattern switching of 65° and 45° in its fundamental mode for the elevation and azimuth planes, respectively. By maintaining the resonant frequency and beamwidth as relatively constant, beam switching is realized using a single feed point

Transparent Patch Antenna on a-Si Thin Film Glass Solar Module

An optically transparent microstrip patch mounted on the surface of a commercially available solar module is proposed. The patch comprises a thin sheet of clear polyester with a conductive coating. The amorphous silicon solar cells in the module are used as both photovoltaic generator and antenna ground plane. The proposed structure provides a peak gain of 3.96 dBi in the 3.4-3.8 GHz range without significantly compromising the light transmission in the module. A comparison between copper and transparent conductors is made in terms of antenna and solar performance. The proposed technique is considerably simpler that previous integration approaches

Dual Band a-Si:H Solar-Slot Antenna for 2.4/5.2GHz WLAN Applications

A simple and compact design of solar-slot antenna for dual band 2.4/5.2GHz wireless local area networks (WLAN) applications is proposed. The design employs amorphous silicon (a-Si:H) solar cells in polyimide substrate with an embedded twin strip slot structure to generate dual resonant frequencies. A T-shaped microstripline feed is used to excite the twin slot in the a-Si:H solar cell. The measured impedance bandwidths for the proposed solar antenna are 25.9% (642 MHz) centered at 2.482 GHz and 8.2% (420 MHz) centered at 5.098 GHz. The measured gain at 2.4 and 5.2 GHz are 3.1 dBi and 2.1 dBi respectively

Wind-driven estuarine turbidity maxima in Mandovi Estuary, central West coast of India

Systematic studies on the suspended particulate matter (SPM) measured on a seasonal cycle in the Mandovi Estuary, Goa indicate that the average concentrations of SPM at the regular station are ~20mg/l, 5mg/l, 19mg/l and 5mg/l for June–September, October–January, February–April and May, respectively. SPM exhibits low-to-moderate correlation with rainfall indicating that SPM is also influenced by other processes. Transect stations reveal that the SPM at sea-end stations of the estuary are at least two orders of magnitude greater than those at the river-end during the monsoon. Estuarine turbidity maximum (ETM) of nearly similar magnitude occurs at the same location in two periods, interrupted by a period with very low SPM concentrations. The ETM occurring in June–September is associated with low salinities; its formation is attributed to the interactions between strong southwesterly winds (5.1–5.6ms-1) and wind-induced waves and tidal currents and, dominant easterly river flow at the mouth of the estuary. The ETM occurring in February–April is associated with high salinity and is conspicuous. The strong NW and SW winds (3.2–3.7ms-1) and wind-driven waves and currents seem to have acted effectively at the mouth of the estuary in developing turbidity maximum. The impact of sea breeze appears nearly same as that of trade winds and cannot be underestimated in sediment resuspension and deposition

Novel Techniques for the Integration of Antennas and Photovoltaic Cells

Various novel approaches to the integration of antenna and photovoltaic technologies are proposed. These include the use of polycrystalline solar cells as groundplane for microstrip patch antennas as well as for reflectors of half-wave dipole antennas. Transparent materials were also evaluated as antenna radiating elements, allowing greater solar efficiency. A novel technique illustrating how emitter-wrap-through rear contact solar cells can be used as a folded-dipole antenna, which is located in the focal line of a parabolic solar concentrator, to provide high solar efficiency as well as high antenna gain, is presented

On Surface Currents in a Polycrystalline Solar Cell Acting as Ground Plane for Microstrip Patch Antennas

The integration of communication devices with photovoltaic (PV) technology leads to the development of autonomous communication systems distinguished by immunity to grid breakdowns and eco-friendliness

Influence of Solar Heating on the Performance of Integrated Solar Cell Microstrip Patch Antennas

The integration of microstrip patch antennas with photovoltaics has been proposed for applications in autonomous wireless communication systems located on building façades. Full integration was achieved using polycrystalline silicon solar cells as both antenna ground plane and direct current power generation in the same device. An overview of the proposed photovoltaic antenna designs is provided and the variation characterised of the electromagnetic properties of the device with temperature and solar radiation. Measurements for both copper and solar antennas are reported on three different commercial laminates with contrasting values for thermal coefficient of the dielectric constant

The nature and distribution of particulate matter in the Mandovi estuary, Central West coast of India

Systematic seasonal variations of suspended particulate matter (SPM) along a 44-km transect of the Mandovi estuary reveal that the concentrations of SPM are low at river-end stations, increase generally seaward, and are highest at sea-end stations of the estuary. An estuarine turbidity maximum (ETM) occurs at sea-end stations during June-September when river discharge is high and also in February-May when river discharge is low. These are the two windiest times of year, the former associated with the southwest monsoon and the latter characterized by a persistent sea breeze. The salinity vs. SPM plot shows that high SPM is a seaward deposit and skewed landward. Suspended matter comprised of floccules, fecal pellets, and aggregates that consist of clay and biogenic particles occur everywhere in the estuary. Diatoms are the most common and are of marine type at the sea-end and freshwater-dominated at river-end stations of the estuary. SPM is characterized by kaolinite- and smectite-rich clay mineral suites at the river- and sea-end stations, respectively. Smectite concentrations increase seawards with the increase in SPM content and are not influenced by salinity. Wind-driven waves and currents and biogeochemical processes at the mouth of estuary likely play an important role in the formation of ETM in resuspension and transformation of SPM into floccules and aggregates and in their upkeep or removal