Design of RF Receiver Front end Subsystems with Low Noise Amplifier and Active Mixer for Intelligent Transportation Systems Application

This paper presents the design, simulation, and characterization of a novel low-noise amplifier (LNA) and active mixer for intelligent transportation system applications. A low noise amplifier is the key component of RF receiver systems. Design, simulation, and characterization of LNA have been performed to obtain the optimum value of noise figure, gain and reflection coefficient. Proposed LNA achieves measured voltage gains of ~18 dB, reflection coefficients of -20 dB, and noise figures of ~2 dB at 5.9 GHz, respectively. The active mixer is a better choice for a modern receiver system over a passive mixer. Key sight advanced design system in conjunction with the electromagnetic simulation tool, has been to obtain the optimal conversion gain and noise figure of the active mixer. The lower and upper resonant frequencies of mixer have been obtained at 2.45 GHz and 5.25 GHz, respectively. The measured conversion gains at lower and upper frequencies are 12 dB and 10.2 dB, respectively. The measured noise figures at lower and upper frequencies are 5.8 dB and 6.5 dB, respectively. The measured mixer interception point at lower and upper frequencies are 3.9 dBm and 4.2 dBm.

A 28 GHz front-end for phased array receivers in 180 nm CMOS process

In this paper, a receiver front-end in 180 nm CMOS operating at 28 GHz is presented. The receiver front-end consists of a cascade low-noise amplifier (LNA) with two gain stages and a current-bleeding active mixer with tunable loads. By embedding a quadrature coupler into the mixer, the circuit delivers in-phase and quadrature outputs. The proposed architecture avoids the traditional I/Q implementation by process-sensitive quadrature voltage control oscillators (VCOs) with larger power consumption at high frequencies. The adopted transformers and inductors are optimized by a momentum tool. The simulated results show that the receiver front-end provides an NF of 5.48 dB, a conversion gain of 18.1 dB, and an IIP3 around −8.5 dBm at 28 GHz. The circuit dissipates 17.3 mW under a 1.8 V supply.

Optimal parametric mixing analysis of active and passive micromixers using Taguchi method

Mixing of fluids flowing through channels and chambers is a crucial step in chemical and biochemical reactions inside microfluidic devices due to laminar flow because of small size channel and chamber dimensions. Mixing can be enhanced by passive or active mechanism which makes convection dominant over diffusion. To address this challenge, the study proposes three novel mixing designs: passive mixer, active mixer and a combination of active and passive mixing. These designs mixing performance has been studied by numerical simulation using COMSOL 5.3. According to the preliminary results of the study, pure active micromixer design has superior mixing ability. The mixing ability was proved by concentration line plots, concentration contours and videos. In order to further optimize the mixing index of the pure active micromixer, Taguchi method is applied against various input parametric values for micromixer such as frequency, voltage and velocity. The velocity is required for two fluids to flow, while frequency and voltages are for providing an external energy for active mixing. A total of nine cases were analyzed; the two best cases out of nine were selected for comparing mixing index line plots. The result of the study conclude that pure active micro-mixer at an optimal set of parameters, frequency of 10 Hz, velocity of 0.05 mm s–1 and voltage of 0.5 V achieved 99.6% mixing index at t = 0.2 s.

A CMOS low-noise active mixer with enhanced linearity and isolation by exploiting capacitive neutralization technique

In this paper, a broadband complementary metal–oxide–semiconductor (CMOS) active down-conversion mixer is presented. Specifically, a capacitor cross-coupled (CCC) transconductor serves as the input stage to reduce noise figure of the mixer while providing wideband input matching. Moreover, a capacitive neutralization technique is used to compensate the source-drain parasitic of input stage and boost loop gain of the transconductor, resulting in improved isolation and linearity. The current-reuse technique applied to the developed transconductor by stacked nMOS/pMOS architecture efficiently saves power consumption of the circuit. Implemented in the TSMC 28-nm CMOS process, post-simulations show that the proposed mixer provides a maximal conversion gain of 11.4 dB and an NF of 3.9–4.7 dB across RF input frequency range of 2–9.6 GHz. The average IIP3 of 5 dBm are obtained while the mixer core consumes 6.2 mW from a 1 V supply.