PERFORMANCE ANALYSIS OF A FLEXIBLE POLYIMIDE BASED DEVICE FOR DISPLACEMENT SENSING

The goal of this paper is to investigate the performance of a wireless passive displacement sensor. Displacement sensor based on the heterogeneous integration process combines traditional fabrication technologies PCB (Printed Circuit Board) and LTCC (Low Temperature Co-fired Technology) with a flexible polyimide foil. The proposed sensor uses the coil as an essential part, multiple spacers and a polyimide foil as a flexible membrane with a piece of ferrite attached to it. With the displacement of the polyimide foil, the ferrite gets closer to the coil causing an increase in its inductance and a decrease of the resonant frequency of the system (coil, ferrite and antenna). Simulation results showed that sensors with equal outer dimensions but different internal structures exhibit different performances. Two prototypes of the sensor with different ferrite dimensions are designed, fabricated and characterized. Finally, their performances are compared

RF equivalent circuit modeling of surface mounted components for PCB applications

Purpose - The appropriate selection of a testing method largely determines the accuracy of a measurement. Parasitic effects associated with test fixture demand a significant consideration in a measurement. The purpose of this paper is to introduce a measurement procedure which can be used for the characterization of surface mount devices (SMD) components, especially devoted to SMD inductors. Design/methodology/approach - The paper describes measurement technique, characterization, and extracting parameters of SMD components for printed circuit board (PCB) applications. The commercially available components (multi-layer chip SMD inductors in the ceramic body) are measured and characterized using a vector network analyzer E5071B and adaptation test fixture on PCB board. Measurement results strongly depend on the choice of the PCB; the behaviour of the component depends on the environment where the component is placed. Findings - The equivalent circuit parameters are extracted in closed form, from an accurate measurement of the board-mounted SMD inductor S-parameters, without the necessity for cumbersome optimization procedures, which normally follow the radio frequency circuit synthesis. Originality/value - It this paper, a new adaptation test fixture in PCB technology is realized. It is modeled and it has provided the extraction of parameters (intrinsic and extrinsic) of SMD inductor with great accuracy

Parameters Extraction of Ferrite EMI Suppressors for PCB Applications Using Microstrip Test Fixture

The goal of this work was to investigate the behavior of a ferrite electromagnetic interference (EMI) suppressor when placed in a real surrounding. Electrical parameter measurements of the same EMI suppressor can differ for different combination of instruments and test fixtures. For that reason specially designed microstrip test fixtures are developed for the vector network analyzer (VNA) measurements. This paper describes the measurement technique, parameters extraction, and characterization of ferrite EMI suppressors for printed circuit board (PCB) applications. Two commercially available components, multilayer chip SMD inductors in a ferrite body, are measured and characterized using a VNA E5071B and developed adaptation test fixture on PCB board. These measurements describe intrinsic and extrinsic parameters of the components and their behavior. If the components are mounted on the PCB, i.e., in a real environment, then the two-port EMI suppressor model with extrinsic parameters has to be used at RF frequencies. The comparison of measured and datasheet values is further presented

Improved Model of T-Type LC EMI Chip Filters Using New Microstrip Test Fixture

In this paper we present an improved model of the multilayered T-type electromagnetic interference chip LC filter for printed circuit board applications, and an improved measurement technique for characterization of such devices. Electrical parameters measurements of the same LC filter can vary for different measurement types. Because of that, we have developed new adaptation microstrip test fixture on printed circuit board for vector network analyzers' measurements of surface mount devices with three terminals. Two commercially available components, multilayer T-type LC filters, are measured and characterized using a vector network analyzer. The comparison of measurement data and simulation values of electrical equivalent circuit and electromagnetic model for two LC filters is further presented. The new improved model of T-type LC filters has provided better agreement between measurement and simulation

Low-Cost CPW Meander Inductors Utilizing Ink-Jet Printing on Flexible Substrate for High-Frequency Applications

This paper describes the design and fabrication of low-cost coplanar waveguide (CPW) miniature meander inductors. Inductors are fabricated on a flexible plastic polyimide foil in ink-jet printed technology with silver nanoparticle ink in a single layer. For the first time, the detailed characterization and simulation of CPW inductors in this technology is reported. The inductors are developed with impressive measured self-resonance frequency up to 18.6 GHz. The 2.107-nH inductor measures only 1 mm x 1.7 mm x 0.075 mm and demonstrates a high level of miniaturization in ink-jet printing technology. The measured response characteristics are in excellent agreement with the predicted simulation response

Influence of Conductive Layer Geometry on Maximal Impedance Frequency Shift of Zig-Zag Ferrite EMI Suppressor

This paper explores an influence of conductive layer geometry on electrical parameters of ferrite electromagnetic interference (EMI) suppressor, which consists of conductive layer in ferrite monolithic structure. Near ferrimagnetic resonant frequency, component has maximal impedance and efficiently suppresses noise. In order to achieve better suppression (i.e., larger impedance), conductive layers should be longer. Nevertheless, longer conductive lines introduce parasitic capacitance, which causes the maximal impedance frequency shift. Because of that, the frequency range where component can be used for efficient EMI suppression is shifted towards lower frequencies, and designing process should be very careful. In this paper, we present simulation of frequency dependent impedance for different geometry parameters of conductive layer. Results for the inductance and the maximal impedance frequency shift of the proposed EMI suppressors are presented in the range 1 MHz-3 GHz. Proposed EMI suppressors were experimentally tested using Agilent 4287A RF LCR meter. Comparison of simulated and measured values of impedance shows a good agreement

Influence of DC Bias on the Electrical Characteristics of SMD Inductors

As the dc bias flows through a ferrite chip surface mount device (SMD) inductor, it tends to premagnetize the core and reduce its inductance and impedance. It is observed that this drop is especially emphasized when the dc current exceeds the safety limit given by the manufacturer. Therefore, it is necessary to investigate and predict the degree of electrical characteristics degradation as well as the dependence of the core losses on core temperature. In this paper, a measurement technique for the investigation of the influence of dc bias on the electrical characteristics of SMD inductors (i.e., inductance, resistance, Q factor, and real and imaginary part of impedance) for printed circuit board applications is presented. Analysis is based on the model of the SMD inductor, which can be presented as a two-port equivalent circuit with intrinsic and extrinsic parameters. For calculation of the parameters of the SMD inductor, extracted from measured S-parameters using vector network analyzer, the in-house software tool IndCalc was used