Miniaturized and tunable 3 dB hybrid and rat-race couplers using capacitively-loaded (C-loaded) transmission lines are designed. Couplers’ compactness has been achieved by substituting the conventional quarter wave transformers in both couplers by their equivalent C-loaded units. The tunable center frequency of the proposed couplers is realized by varying the transmission line loading capacitan...

This paper presents the analysis of the Darlington pair as an element in a distributed amplifier (DA) configuration. The Darlington pair circuit with the input and output inductor of the DA transmission line are included in the analysis of the circuit, this is also simulated. The inherent problem of poor performance is reduced by the inductors. The overall result shows that high power gain at h...

Absorption spectroscopy with tunable diode lasers (TDLAS) in the infrared region is a well-known technique for the chemical analysis of gas mixtures. The laser provides a high selectivity, which is important in industrial environments such as in-line stack monitoring, where complex gas mixtures are present. A wavelength tunable diode laser in the near infrared region has been utilized as a ligh...

We propose a procedure for transferring the state a microwave qubit via a transmission line from one resonator to another resonator, with a theoretical efficiency arbitrarily close to 100%. The emission and capture of the microwave energy is performed using tunable couplers, whose transmission coefficients vary in time. Using the superconducting phase qubit technology and tunable couplers with ...

We demonstrate a high-gain low-noise double-pass tunable EDFA over S- and C+L-bands by discretely introducing fundamental-mode leakage loss in a 16-m-long standard C-band Er(3+)-doped fiber. The amplified spontaneous emission at the wavelengths of longer than 1530 nm can be substantially attenuated by the ASE suppressing filters to maintain high population inversion and to squeeze out the optic...

This paper describes a CMOS analog baseband circuits for directconversion receiver of5GHz IEEE 802.11a. The analog baseband consists of I/Q signal paths which have channel selection filter, programmable gain amplifier (PGA). An active-RC channel selection filter for WLAN is described whose cut-off frequency is tunable from 6MHz to 20MHz. For high linearity, the PGA is constructed with op-amp an...

— In this paper, a novel notch resonator is proposed based on Rectangular Split Ring Resonator (R-RSS) element. We represented the electrical characteristics for R-SRR elements coupled with microstrip line, and measured result is compared with electromagnetic simulation (HFSS) result. We also solved equivalent circuit for R-SRR element, and also discussed influences of change structural paramet...

A detailed description is presented for a tunable far infrared laser spectrometer based on frequency mixing of an optically pumped molecular gas laser with tunable microwave radiation in a Schottky point contact diode. The system has been operated on over 30 laser lines in the range 10-100 cmi and exhibits a maximum absorption sensitivity near one part in 106. Each laser line can be tuned by f ...

*Correspondence: Guoping Dong and Jianrong Qiu, State Key Laboratory of Luminescent Materials and Device, School of Materials Science and Engineering, South China University of Technology, Wushan Road 381, Tianhe District, Guangzhou, Guangzhou 510640, China e-mail: [email protected]; [email protected] Quantum dot (QD)-doped glasses have been the hotspot for their excellent electronic and optical pr...

Two-dimensional temperature measurements using filtered Rayleigh scattering (FRS) have been demonstrated. A tunable single-longitudinal-mode alexandrite laser was employed to provide the tunable narrow-line-width ultraviolet laser beam at 254 nm. Isotopic-enhanced mercury was utilized as an ultraviolet atomic filter. The strong absorption of the filter enabled effective suppression of elastic b...