Lj. Zivanov

Comparative characteristics of thick-film integrated LC filters

The paper describes the design, fabrication and test of integrated LC filters in thick film technology. The range of filters was electrically characterized using a HP 8566B network analyzer. We present a scalable analytical model for thick film integrated LC filters that is suitable for design and circuit simulations. We also provide simple expressions for evaluating the optimum conductor thicknesses.

Micro force sensor fabricated in the LTCC technology

This paper presents resonant force sensor designed for the operation in the MHz range and for 0 to 6 N load. The LTCC technology is implemented for the sensor fabrication and a wireless readout of the measured data is provided. Used LTCC tape is characterised in order to demonstrate its mechanical and electrical properties at room temperature. Also, theoretical model of the sensor is developed to predict its behaviour. Fabricated sensor performance is experimentally characterised and obtained results are in good agreement with the ones derived from the presented theoretical model.

Planar inductive sensor for small displacement

This paper presents a meander type displacement inductive sensor, developed in printed circuit board (PCB) technology. It also describes design, realization and the input inductance measurement of sensor. The displacement in two directions (less than 0.5 mm) can be detected by using two sensors elements (i.e. two pairs of meander coils). In each pair, one of the coils is fixed, and between its terminals the input inductance was measured, while other coil is short-circuited. If one coil is moved above the other in directions of x- and z-axes, coupling between coils will change, as well as input inductance, which serves as a measure of displacement. In order to achieve better linearity of the sensor, gap is inserted in the middle of each conductive segment of fixed coils. Four sets of inductive sensors were realized: without gap and with three different gaps: 0.25 mm, 0.51 mm and 0.76 mm. In addition, a simple model of the inductive sensor is proposed. Using this model, the input inductance of displacement sensor was calculated and compared with measured values. A good agreement was found.

Comparison of optimal design of different spiral inductors

One of the key components in many RF ICs applications is the inductor. It is very important that inductor has optimal design, that means, optimal geometry with the best possible characteristics. In this work optimal design of square, octagonal, and circular spiral inductors are compared. Our optimization algorithm is based on compact model, where the physical behavior is described through analytical expressions in geometric programming (GP) form. Globally optimal trade-off curves between maximum Q-factor or self-resonance frequency and inductance are presented. Results of our software tool show that the best layout of spiral inductor is circular then octagonal and square spiral.

Analysis of Effects of Dielectric and Material Characteristics on the Performance of Thick Film Thermistors Using Commercial Software Tools

In this paper an alternative approach to analysis of NTC thermistors based on the use of commercial electromagnetic simulator tool is presented. Structure analyzed was a thick film segmented NTC thermistor. Influence of the material characteristics of thermistor paste used on the overall thermistor performance was analyzed and simulated. Obtained simulation results were compared with experimental results and validity of the adopted approach was verified

Analysis of effects of material and geometrical characteristics on the performance of SMD common mode choke

In this paper, proposed structures of ferrite common mode chokes for suppression of conductive electromagnetic interference (EMI) will be presented. These surface-mount devices are widely used in modern electronic equipment for suppression or reduction of EMI. Choke consists of two multilayer spiral type inductors, embedded in ferrite monolithic structure. To obtain the optimal design of choke, the simulation tool ILCMC for calculation of insertion loss of common mode choke is developed. Using ILCMC we have simulate the effects of material and geometrical characteristics on the common mode choke performance. Insertion losses of proposed components are calculated and compared. Goal of this paper is to explore the optimal design of EMI chokes. These simulation results will be very useful for construction of the ferrite common mode chokes.

Modelling and Characterisation of Fractal Based RF Inductors on Silicon Substrate

This paper offers a new realisation of a lumped element model for the second order Hilbert type fractal inductor on silicon substrate. Modelled elements are derived and analytically determined from the inductors layout specifications and available materials parameters. Based on the presented concept, frequency dependent characteristics for fractals inductance and quality factor (Q-factor) can be anticipated easily and with acceptable tolerances. In order to verify the accuracy of the presented model obtained parameters have been compared with experimentally attained values. Determined model parameters show satisfactory compliance with electrical parameters attained through experimental measurement, for frequencies in lower RF range (up to 10 GHz).

Design and Simulation of Thick Film Thermistors Using Commercial Simulation Tools

Methods for predicting and analyzing the behavior of NTC thermistors have remained the same and they typically include accurate measurements of resistance and temperature, followed by curve-fitting methodologies for determining the relationship of temperature to resistance for similar thermistor devices. In this paper, new approach based on using commercial software tools was applied on the thick film segmented thermistor models. Obtained simulation results were compared with experimental results and validity of the adopted approach verified. Realized segmented thermistors were made of a low temperature NTC thick film paste NTC 3K3 95/2 with nanometer particle powder printed on alumina

Analysis, modeling and optimization of thick film solenoid-bar type inductors and transformers

Solenoid-bar type inductors and transformers with different turns ratio are analyzed. In this paper in equivalent circuit models for inductors and transformers are presented. Parasitic physical phenomena important to prediciton of inductor quality factor Q are included in the model, and special attention is paid to inductance calculations.

Realization of high quality RF inductors using LTCC technology

This article offers a detail description of design, simulation, fabrication and characterization of buried inductors on two different substrate configurations intended for application in the radio frequency range. The presented inductors are meander type structures fabricated using LTCC (Low Temperature Co-fired Ceramic) technology. Different substrate configurations incorporate placement of an air-gap beneath the inductor. Obtained results present over 25% increase in quality factor and widening of the operating frequency range by over 45% in comparison with inductors on standard substrate configurations.