In this paper, microstrip-based spiral structured artificial magnetic media (metamaterial) coupled with microfluidic channel is experimentally demonstrated for sensing applications. It is found that the resonant frequency and the amplitude changes due to dielectric loading from the introduction of chemical substances in the microfluidic channels. Different concentrations of water -methanol and water -isopropanol samples are used in the characterization of the sensor. For water -methanol mixtures, the resonant frequency shifts from 2.15 GHz to 2.0 GHz with change in dielectric constant from 25 to 75. Results show that the wave propagation in LH-media can be used for interrogation of minute volumes of samples with high sensitivity.
IntroductionRapid characterization of chemical and biological samples is increasingly important in clinical, security, safety, drug discovery and industrial applications. Sensing approaches are needed that does not require tagging, (e.g., using fluorescent markers) in order to maintain the samples in their original form while under study. Along with rapid label-free characterization, interrogation of small sample volumes is critically needed in the areas of clinical diagnosis and drug discovery. In this paper, periodic media co-integrated with microfluidic leading to a novel RF near-field sensor is implemented to tackle these challenges. The proposed sensor is simple, cost effective, and can be used for label-free sensing and detection Spiral structured artificial magnetic media (metamaterial) designs have been widely used in the design of compact coplanar waveguides (CPW) and microstrip-based circuit topologies. Recently, split-ring based metamaterial structures that are edge-coupled to a microstrip line have been used in the sensing of biomolecules [1]. In this structure, the interrogation signal (RF) edge couples from a microstrip transmission line to a ring resonator. The biomolecules are made to bind onto the ring resonator. A direct approach of interrogation will be desirable which is more compact and provides improved sensitivity and yet still simple to fabricate and implement. To meet this goal, in this paper, metamaterial structure that is integral part of the microstrip line is employed for sensing application. A spiral based metamaterial transmission was recently introduced, [2 -3], and this design is implemented here for sensing applications.In spiral based metamaterial transmission lines, the periodic arrays of the spiral structure employ left-handed (LH) propagation properties and support backward waves at their fundamental resonance [2]. Motivated by the wave propagation phenomenon of this medium, a microfluidic sensor that interrogates samples in the near-field region is attractive to achieve high sensitivity using low-volumes of samples. This sensor is designed and implemented for
This paper investigates channel/link frequency domain compliance in order to predict compatibility with a bus's chip I/O circuitry at its ends. Any channel can be associated with certain frequency domain parameter values which are easily calculated from the channel S-parameter matrix. A set of frequency domain parameters that can sufficiently describe a channel are defined in this paper. Using a genetic algorithm, the frequency domain parameter bounds in a multidimensional space describing PCIe-Gen3 (bus speed = 8 Gb/s) compliant channels are found. Details of the methodology used in order to arrive at the multidimensional frequency domain compliance model, model results and model simulation validation testing are presented.
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