Low Adjacent Channel Leakage Research Articles

Analysis of peak-to-average power ratio in filter bank multicarrier with offset quadrature amplitude modulation systems using partial transmit sequence with shuffled frog leap optimization technique

<p class="Abstract">Because of its low adjacent channel leakage ratio, the Filter Bank Multicarrier with Offset Quadrature Amplitude Modulation (FBMC-OQAM) has sparked the attention of many researchers in recent times. However, the problem of high Peak-to-Average Power Ratio (PAPR) measurement has a detrimental influence upon the FBMC system's energy measurement efficiency. We study PAPR reduction of FBMC-OQAM signals using the Partial Transmit Sequence (PTS) methods in this work. The PTS with shuffled frog leap phase optimization method is proposed in this paper to reduce the larger PAPR measurement, which is the major disadvantage of the filter bank multicarrier with offset quadrature amplitude modulation system. According to the simulation software findings, the suggested approach has a considerably superior PAPR, which may reduce the PAPR by about 2 dB at complementary cumulative distribution function 10<sup>-3</sup> when compared to the traditional PTS method, and it has a much lower computational complexity than the previous ways. The experimental parameters are measured, and results are evaluated using MATLAB tool.</p>

Evaluation of Clipping Based Iterative PAPR Reduction Techniques for FBMC Systems

This paper investigates filter bankmulticarrier (FBMC), a multicarrier modulation technique exhibiting an extremely low adjacent channel leakage ratio (ACLR) compared to conventional orthogonal frequency division multiplexing (OFDM) technique. The low ACLR of the transmitted FBMC signal makes it especially favorable in cognitive radio applications, where strict requirements are posed on out-of-band radiation. Large dynamic range resulting in high peak-to-average power ratio (PAPR) is characteristic of all sorts of multicarrier signals. The advantageous spectral properties of the high-PAPR FBMC signal are significantly degraded if nonlinearities are present in the transceiver chain. Spectral regrowth may appear, causing harmful interference in the neighboring frequency bands. This paper presents novel clipping based PAPR reduction techniques, evaluated and compared by simulations and measurements, with an emphasis on spectral aspects. The paper gives an overall comparison of PAPR reduction techniques, focusing on the reduction of the dynamic range of FBMC signals without increasing out-of-band radiation. An overview is presented on transmitter oriented techniques employing baseband clipping, which can maintain the system performance with a desired bit error rate (BER).

A Self-Aligned Gate AlGaAs/GaAs Heterostructure Field-Effect Transistor with an Ion-Implanted Buried-Channel for use in High Efficiency Power Amplifiers

In this paper we report on a self-aligned gate buried-channel Al0.22Ga0.78As/GaAs heterostructure field-effect transistor (BC-HFET). The BC-HFET comprises a selectively ion-implanted channel and an undoped i-AlGaAs surface layer. In order to realize the buried channel heterostructure, a combined process of ion-implantation and epitaxial growth is developed. The post-implantation annealing before the epitaxial growth successfully reduces the interdiffusion at the heterointerface between the ion-implanted GaAs channel and the AlGaAs surface layer. The BC-HFET overcomes the disadvantages of a low breakdown voltage which exists in conventional self-aligned gate MESFETs. The BC-HFET exhibits a high breakdown voltage of 8 V and a high Schottky barrier height of 0.75 eV. The 1-mm-wide power BC-HFET demonstrates an output power of 18.2 dBm and a drain efficiency of 50% at a low adjacent channel leakage power of -59 dBc for a 1.9-GHz π/4-shifted quadrature phase shift keying (QPSK) modulated input, for use as Personal Handy-phone System handsets.

2-V-operation /spl delta/-doped power HEMT's for personal handy-phone systems

A high-efficiency and high-power-density /spl delta/-doped AlGaAs/InGaAs HEMT with low adjacent channel leakage has been developed for the digital wireless personal handy-phone system (PHS). When qualified by 1.9-GHz /spl pi//4-shifted quadrature phase shift keying (QPSK) modulated PHS standard signals, the 2.0-V-operation HEMT with a 1-mm gate width demonstrated a power-added efficiency of 45.3% and an output power density of 105 mW/mm. This is the highest power density ever reported by power transistors for the PHS. State-of-the-art results for the PHS operating at 2.0 V were achieved by the S-doped power HEMT for the first time.

High-efficiency low adjacent channel leakage GaAs power MMIC for 1.9 GHz digital cordless phones

We report on the fabrication of highly efficient GaAs MESFET's, the design for low distortion, and the performance of this MMIC. Two power MESFET's and input, interstage, and output matching circuits were integrated in a very small chip size of 1.0 mm/spl times/1.5 mm. This MMIC achieved an output power of 22 dBm at 1.9 GHz with high power added efficiency of 49.5% and low adjacent channel leakage power of -56 dBc under the low operating voltage of 3.0 V. This result represents one of the highest efficiencies that have been reported. This MMIC has a promising future for 1.9 GHz digital cordless phone applications.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Refractory WNx/W Self-Aligned Gate GaAs Power Metal-Semiconductor Field-Effect Transistor for 1.9-GHz Digital Mobile Communication System Operating with a Single Low-Voltage Supply

We have developed a refractory WNx /W self-aligned gate GaAs power metal-semiconductor field-effect transistor (MESFET) for use in L-band digital mobile communication systems. This power MESFET operates with high efficiency and low distortion at a gate bias of 0 V and a low drain bias of 2.7 V, because of its small drain knee voltage, high transconductance and sufficient breakdown voltage. This power MESFET is quite promising for a highly efficient linear power amplifier IC operating with a single low-voltage supply. Good output characteristics of the power MESFET with 1 mm gate width were attained for π/4-shifted quadrature phase shift keying (QPSK) modulated input signals in the 1.9-GHz band, such as an output power of 18.4 dBm, a power gain of 19.0 dB and a high power-added efficiency of 26.4% when a sufficiently low adjacent channel leakage power of -58 dBc was obtained.