An antenna comprising two different composite right/left-handed transmission line structures is proposed which enables easy beam steering at an operation frequency of 10 GHz. The composite right/left-handed transmission lines are based on planar, periodically arranged via free unit cells, implemented in microstrip technology. Both transmission lines exhibit the infinite wavelength phenomenon wh...

Tunability is one of the key aspects of any laser system. In High-Gain Harmonic Generation Free Electron Laser (HGHG FEL) the seed laser determines the output wavelength. Conventional scheme of tunable HGHG FEL requires tunable seed laser. The alternative scheme [1] is based on compression of the electron bunch with energytime correlation (chirped bunch) in the FEL dispersive section. The chirp...

This letter presents a compact metamaterial-based tunable zeroth-order resonant antenna. It is based on the double-negative unit cell with a function of tunable inductance realized by a varactor and impedance convertor in the shunt branch. The resonant frequency of the designed antenna ranges from 2.31 to 3.08 GHz, depending on the capacitance of the used varactor. Its size is very compact (0.0...

This paper presents a novel variable gain amplifier (VGA) design which is applied in the automatic gain control (AGC) loop of DVB-T/H receivers. The VGA composed of three cascaded tunable gain stages to provide a 70 dB dynamic range with 2 dB gain steps. Each gain stage is based on a digital variable gain amplifier (DVGA) which is composed of a plurality of gain blocks (GBs) and a fully differe...

In this paper, very high frequency (VHF) current and voltage biquadratic lowpass filters implemented directly by the linear wideband finite-gain current and voltage amplifiers, respectively, are proposed and analyzed. A new Q-enhancement circuit which consists of a finite-gain wideband tunable voltage amplifier and a Miller capacitor is also proposed. It can increase the maximum-gain frequency ...

In this paper, we numerically simulated a glass-based all-optical 1×N power splitter with eleven different configurations using soliton breakup in a nonlinear medium. It is shown that in addition to reconfigurability of the proposed splitter, its power splitting ratio is tunable up to some extent values too. Nonlinear semivectorial iterative finite difference beam propagation method (IFD-...

We report the design and experimental measurement of a powered active magnetic metamaterial with tunable permeability. The unit cell is based on the combination of an embedded radiofrequency amplifier and a tunable phase shifter, which together control the response of the medium. The measurements show that a negative permeability metamaterial with zero loss or even gain can be achieved through ...

this paper proposes a new smart antenna beamforming scheme based on electronically steerable parasitic array radiator (espar). the proposed method is capable of providing better capacity compared to the conventional espar. the termination of each antenna element in this structure comprises a pin diode in addition to a varactor. using pin diode besides the varactor provides more degrees of freed...

A square-law harmonic-rejection mixer (SL-HRM) driven by a sine local oscillator (LO) is proposed for wideband and tunable rejection of all LO harmonics. The key performances including the gain, noise figure (NF), input-referred third-order intercept point (IIP3), and harmonic rejection ratio (HRR) with respect to the amplitude and purity of the sine-LO are analyzed. In the circuit level, the S...