In this paper, a dual notch Ultra Wideband (UWB) monopole antenna with compact dimensions of 37.8 × 27.1 × 1.6 mm 3 is presented. Octagon patch with a defected ground structure is used to attain the wide frequency range of 3.17 GHz-11.61 GHz with ultra-wide impedance bandwidth of 8.33 GHz. The band notch characteristics in WiMAX (3.2 GHz-3.67 GHz) and WLAN (4.32 GHz-5.81 GHz) bands are achieved using inverted pi-slot in the radiating element and a pair of double split ring resonators (DSRRs) on either sides of the feed, respectively. Reconfigurability in the bands is obtained by using BAR64-03W pin diodes switching at the appropriate placement in the antenna structure. The proposed antenna exhibits efficiency of 88% in operating and 20% in nonoperating frequencies. The proposed antenna is designed, simulated, and optimized using HFSS 19 electromagnetic tool. The measured results are tested using combinational analyzer in a chamber with antenna measurement setup for validation and found in good matching with simulation.

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In(Ga)As/GaAs-based quantum dot infrared photodetectors (QDIPs) have emerged as one of the most suitable devices for infrared detection. However, quantum dot devices suffer from lower efficiencies due to a low fill-factor (∼20%–25%) of dots. Here, we report a post-growth technique for improving the QDIP performance using low energy light ion (H−) implantation. At high bias, there is evidence of suppression in the field-assisted tunneling component of the dark current. Enhancement in peak detectivity (D*), a measure of the signal-to-noise ratio, by more than one order, from ∼109 to 2.44 × 1010 cm Hz1/2/W was obtained from the implanted devices.

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