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The design and realization of a compact coplanar waveguide (CPW) fed ultrawideband (UWB) antenna having dual‐notched bands is presented in this article. The antenna possesses on demand notch bands at 4 to 5.78 GHz and 6.83 to 8.22 GHz. The presented design consists of a single iterated octagonal patch antenna designed on cheap FR4 substrate. The stub is utilized to achieve a wide impedance matching of 7.33 GHz (3.2‐10.5 GHz), while the notch‐bands are realized using split ring circular slots. These notch‐bands are controlled independently without affecting the overall performance of the antenna. Simulated and measured results showed that the antenna offers excellent performance with an overall size of 20 × 23 mm2, high efficiency of more than 90%, and a nearly omnidirectional maximum gain of 4.8 dBi. The performance of the proposed antenna is better than the antennas presented in the literature in term of size, stable gain, and independently controllable notch bands. Besides these advantages, the compact size allows the antenna to integrate into small devices easily and help manufacturers to produce a massive number of antennas comfortably.

<p>Maximum power point tracking (MPPT) algorithms are employed in photovoltaic (PV) systems to make full utilization of PV array output power, which have a complex relationship between ambient temperature and solar irradiation. The power-voltage characteristic of PV array operating under partial shading conditions (PSC) exhibits multiple local maximum power points (LMPP). In this paper, an advanced algorithm has been presented to track the global maximum power point (GMPP) of PV. Compared with the Perturb and Observe (P&amp;O) techniques, the algorithm proposed the advantages of determining the location of GMPP whether partial shading is present.</p>

In the aim to contribute to the security of medical image, we present a robust watermarking method which combines discrete wavelet transform (DWT), discrete cosine transform (DCT) and singular value decomposition (SVD). This approach is intended to insert an invisible image watermark in a medical image. The cover medical image is divided up into the third level of DWT coefficients and then is transformed by DCT and SVD. The same procedure is applied to the watermark image. The singular value of watermark is inserted into the singular value of the high-frequency sub bands of the third level DWT of the cover image. However, the insertion of the watermark in these areas makes it possible to reinforce the robustness of the system of watermarking without hindering the quality of the watermarked image. The performance of the proposed method was evaluated in term of invisibility by calculating the Peak Signal to Noise Ratio (PSNR) between the original and the watermarked image and in term of robustness by measuring the normalized correlation coefficient (NC) between the original watermark and the extracted watermark after applying attacks. The experimental results approve that our proposed hybrid algorithm gives an excellent compromise imperceptibility and robustness against several attacks such as Gaussian noise, Saltand-Pepper, Speckle noise, Average filter, Median filter, and Wiener filter compared with existing methods.