A new shaped circularly polarized dielectric resonator antenna (CP DRA) is studied with branch-line coupler and log-periodic balun for the GPS application. Since the coupler and balun are located under the DRA, it does not increase the footprint of the antenna, as a result the system is very compact. Two configurations are considered in this paper. In the first configuration, an external 50Ω lo...

Dimensionless conductance for light propagating through a random medium with amplification tends to diverge with an increase of gain. This raises questions on the applicability of the localization criteria based on this quantity. To circumvent this problem, we study the properties of the ratio between the transmission (conductance) and the energy stored in the random medium. We argue that the g...

This paper presents a fully integrated CMOS Vband Injection-Locked Power Amplifier (ILPA) for phase and frequency modulated millimeter-Wave (mm-Wave) transmitter. At mm-Wave frequency, multi-stage PAs are usually employed to achieve enough power gain due to low power gain of CMOS transistor even though it has low power efficiency. This work investigates mm-Wave ILPA for constant envelope modula...

An Ultrawideband (UWB) high gain compact Vivaldi antenna with end fire radiation patterns is presented for radar and microwave imaging applications. The antenna is operating for 2.9GHz to more than 11GHz with -10dB impedance bandwidth and is designed on low cost FR4 substrate of thickness 0.8mm. While designing the proposed antenna, initially a compact exponential tapered slot Vivaldi antenna i...

Here we report a compact monolithic 2000nm pulsed laser with a single spatial mode output, ~1.5ns pulse duration, 8kW peak power and >200mW average power at 20 kHz repetition rate. The gain-switched laser, consisting of a pair of fiber Bragg gratings and 0.5m of thulium-doped single cladding fiber, was core pumped by a high peak power pulsed 1.5 m laser. When the input pulse energy of the 20 kH...

A compact planar monopole UWB antenna with quadruple band-notched characteristics is analyzed and presented. By introducing a C-shaped slot, nested C-shaped slot in the radiating patch and U-shaped slot in the feed line, quadruple band-notched characteristics are achieved at frequencies of 2.5, 3.7, 5.8 and 8.2 GHz. The proposed antenna has been fabricated and tested. Measured impedance bandwid...

In this paper, a novel multiple slot microstrip patch antenna with enhanced bandwidth is presented. The design adopts contemporary techniques namely; probe feeding, inverted patch structure and multiple slotted patch. The composite effect of integrating these techniques and by introducing the novel multiple shaped patch, offer a low profile, wide bandwidth, high gain and compact antenna element...

In this paper, a compact band-notched UWB planar antenna with Transmission-Line-fed is presented and I’m using a new technique by etching a narrowband resonance H-shape slot in the ground plane of the antenna. This antenna is capable reducing the interference at the WLAN bands by eliminating the 4.85–6.17 GHz band. The proposed antenna has compact size of 16 × 22 mm2 including the ground plane ...

We show that plasmons in two-dimensional graphene can have net gain at terahertz frequencies. The coupling of the plasmons to interband electron-hole transitions in population inverted graphene layers can lead to plasmon amplification through the process of stimulated emission. We show that the net gain values can exceed 10 cm−1 in the 1-10 terahertz frequency range, for electron-hole densities...