Wideband Slot Array Antenna Fed by Gap Waveguide with Right-Handed Circular Polarization and High Gain

A wideband and high-gain circularly polarized (CP) 16 × 16 array antenna based on gap waveguide technology is presented for millimeter-wave applications at 28 GHz frequency range. Four cavity-backed slots with linear polarized (LP) radiation are used as the subarray. CP is obtained by a 4 × 4 sequential feeding network which is also expanded to achieve high gain. The feeding network of the final array antenna consists of two layers based on the ridge gap waveguide (RGW), and it has four unconnected metal layers. It is shown by simulation that the proposed antenna has 20.5% impedance bandwidth over 25.8–31.7 GHz and 3 dB axial ratio bandwidth near 10% over 27.2–30 GHz. In addition, the maximum gain value for this antenna is 31.6 dBi at a frequency of 29 GHz, which shows good performance compared to other structures.

Performance Analysis of 33KW Grid Connected Solar Roof Top Power Plant

Solar Roof tops are being progressively used worldwide now a days to install solar panels to generate electricity. One such step has been taken by S.R.K.R Engineering College to generate power through solar roof tops by installing a 33KWp On-grid solar power system (Latitude 16.54° N and Longitude 81.50° E) during April-2016. This grid connected PV system is installed at an area of 345 sq. m and the PV modules are tilted at an angle of 18° on the top of a 3 staired building. This paper analyses the Performance of a 33KWp On-grid photovoltaic system which is monitored between Jan-2019 to Dec-2019. Some part of electricity generated by the system is consumed by the college and the remaining power was fed in to the state grid. The tariff for the grid connected system is based on the energy consumed from the grid and the energy supplied in to the grid. The data is collected from the Data-logger of the inverter which is having an IP address. This data is collected according to the IEC protocol which suggests to collect the data for every 15 minutes. The data is collected from the inverter in this format and is stored as a csv file every day. This data along with the meteorological data collected from the coordinates of the site are analyzed by using pvsyst simulation software. The performance of this system is found for the third year in operation. . The analysis of the PV system has been done to enumerate its performance at each and every component and thereby develop solution to mitigate the problems. The different parameters including efficiencies of panels, inverter, array’s initial yield, final array yield, and the performance ratio of PV system are analyzed.

Contact Pin-Printing onto Porous Silicon for Creating Microarrays with High Chemical Diversity

We explore the size and spatial microheterogeneity of contact pin-printed spots formed on porous silicon (pSi). Glycerol was contact printed at room temperature onto as-prepared, hydrogen-passivated pSi (ap-pSi) using 50 or 200 µm diameter solid pins. The pSi was then subjected to a strong oxidizing environment (gaseous O3) and washed to remove the glycerol masks. The glycerol-free regions were converted to oxidized pSi (ox-pSi); the glycerol-coated regions were protected from O3, but not entirely. The final array is described as circularly shaped “ap-pSi” regions on a field of ox-pSi. When comparing the areas outside and inside the glycerol-masked pSi spots, one finds dramatic differences in the Si–O–Si, SiH x ( x = 1–3) and O ySiH x ( y, x = 1–3) levels with a spatially dependent continuum of compositions across the spot diameter. Experimental conditions could be adjusted to tune the final ap-pSi spot diameter and edge widths from 90 µm to 520 µm and 20 µm to 130 µm, respectively. The resulting ap-pSi spot diameter is explained by using molecular kinetic theory and time-dependent glycerol imbibement into the pSi within a one-dimensional Darcy’s law model.

An Iterative Technique for the Synthesis of Active Antenna Oscillator Arrays

A design procedure for the synthesis of a coupled active antenna oscillator array is presented. Such an array is synthesized by deriving two sets of parameters: the radiators' positions and the oscillators' outputs. The outputs are used to excite the radiators. Minimization of the mean square error between the desired pattern and the resulting one is made. Synthesis starts from an initial array, which is perturbed iteratively by varying simultaneously the element excitations and positions. In the iteration, the first variation of the cost function is set equal to zero. The final array results from the last iteration, where the stopping criteria are met. The procedure designs simultaneously both the antenna and the attached coupled oscillator array providing viable solutions. The second by properly configuring the tuning parameters through the use of closed-form formulas. The resulting arrays are shown to comply with the desired pattern and the nonlinear dynamics thus proving the validity of our method.

NEUTRINO ASTRONOMY AND COSMIC RAYS AT THE SOUTH POLE: LATEST RESULTS FROM AMANDA AND PERSPECTIVES FOR ICECUBE

The AMANDA neutrino telescope has been in operation at the South Pole since 1996. The present final array configuration, operational since 2000, consists of 677 photomultiplier tubes arranged in 19 strings, buried at depths between 1500 and 2000 m in the ice. The most recent results on a multi-year search for point sources of neutrinos will be shown. The study of events triggered in coincidence with the surface array SPASE and AMANDA provided a result on cosmic ray composition. Expected improvements from IceCube/IceTop will also be discussed.

Seismic array design by spatial convolution

Deriving the response of an array is one thing, designing an array to match a desired response is quite another. The first is easy, the second is not. Given a selected pass and reject requirement in the spatial frequency domain, an array can be obtained that best matches such requirement within the limits of available hardware. Optimum spatial arrays for 2‐D and 3‐D/4‐D seismic surveys can be designed using the technique of spatial convolution. Such a technique relies upon uniform arrays of differing shapes and sizes as building blocks. These building blocks are convolved in space because their selected responses matching notch points against side lobes to achieve a desired end result in the spatial frequency domain. The final array design can be made optimum for a given set of requirements, such as signal preservation within the passband, attenuation within the reject band, and azimuthal distribution for 3‐D/4‐D seismic surveys. For any given design, solely the number and the spacing of the elements limit the optimization. A rule of thumb has been observed which shows that the required number of elements in a 2‐D array for 3‐D/4‐D seismic is equal to the square of the number of elements in a 1‐D equivalent array for 2‐D seismic. It is also observed that for a given number of elements, narrow azimuth designs can offer greater attenuation than wide azimuth designs.

Vibration Analysis of Single Element Transducer in Acoustic Arrays

This paper offers a method for the vibration analysis of single element transducer in acoustic arrays as a damped multi-degree of freedom mechanical system with forced excitation at the fundamental thickness mode. The link between the frequency response and the element structural modal shape is analyzed and a method for controlling these modes such that they introduce no artifacts in the performance of the final array and imaging system is discussed.