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SUMMARYA new method to decrease the phase noise of the sinusoidal oscillators is proposed. The proposed method is based on using a dynamic transistor biasing in a typical oscillator topology. This method uses the oscillator impulse sensitivity function (ISF) shaping to reduce the sensitivity of the oscillator to the transistor noise and as a result reducing the oscillator phase noise. A 1.8 GHz, 1.8 V designed oscillator based on the proposed method shows a phase noise of −130.3dBc/Hz at 1 MHz offset frequency, thereby showing about 6 dB phase noise decreasing in comparison with the typical constant bias topology. This result is obtained from the simulation based on 0.18u CMOS technology and on-chip spiral inductor with a quality factor equal to 8.

Abstract-Every generation of mobile communication has been associated with higher data rates than the previous generation. So 5G new spectrum radio access should support data rates exceeding 10 Gbps in most of its applications. An Ultra Wide Band (UWB) ultrahigh data rate full six-port receiver architecture up to 6.7 Gbps for 5G new spectrum is presented in this paper. The proposed structure is constructed using one UWB ultra-high data rate Wilkinson power divider/combiner and three UWB ultra-high data rate two-stage branch line couplers which are the essential components of any full sixport structure. The design procedure, optimization and implementation of these two UWB essential components in 21-30 GHz are completely done to achieve the optimum performance of final six-port structure. The final fabrication results show the average of −14 dB of input matching, −20 dB of isolation of isolated Ports, −4.2 dB of coupling in output ports (considering 2 SMA connectors and transitions in each path), and linear phase variation of outputs in the whole bandwidth of 21-30 GHz. To analyze and qualify the UWB six-port structure in any specific application in 5G and other UWB high data rate applications, a new analytical formulation with a new six-port structure of non-ideal UWB six-port circuit is presented. With this new analytical model and new configuration, there is no need to calibrate the outputs of in-phase and quad phase of the six-port receiver outputs. Based on the final fabricated essential components and the new analytical model, the final full six-port structure is constructed and analysed using UWB-OFDM with QPSK and 16QAM demodulation schemes in its sub-bands. To complete and verify the new analysis and to validate the final constructed UWB six-port structure and its essential components in ultra-high data rate application in 5G new spectrum, the UWB-IR impulse radio with modulated ultra-high data rate signal up to 7 Gbps and in 21-30 GHz bandwidth is completely discussed. The results show that all clusters of demodulated constellations are very well positioned and individualized in whole bandwidth in all modulation schemes. Also this new design and configuration of six-port receiver improves the dynamic range of the RF input signals up to 60 dB which is valuable. During the design procedure, a very useful method to choose the suitable laminate based on the time, frequency and two dimensional Wigner-Vile Distribution methods is presented. Also, some practical issues in design and implementation of the UWB microstrip component such as transitions are considered to achieve the best results.

We propose a new method for practical non-Gaussian and nonstationary underwater noise modeling. This model is very useful for passive sonar in shallow waters. In this application, measurement of additive noise in natural environment and exhibits shows that noise can sometimes be significantly non-Gaussian and a time-varying feature especially in the variance. Therefore, signal processing algorithms such as direction-finding that is optimized for Gaussian noise may degrade significantly in this environment. Generalized autoregressive conditional heteroscedasticity (GARCH) models are suitable for heavy tailed PDFs and time-varying variances of stochastic process. We use a more realistic GARCH-based noise model in the maximum-likelihood approach for the estimation of direction-of-arrivals (DOAs) of impinging sources onto a linear array, and demonstrate using measured noise that this approach is feasible for the additive noise and direction finding in an underwater environment.

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