Andrei Silaghi

• Doctor of Engineering
• Professor (Associate) at Polytechnic University of Timişoara

This paper presents a new SiGe HBT-based high dynamic range double-balanced down-conversion differential mixer. Operating within the 0.5 GHz to 1.8 GHz range, the suggested mixer is appropriate for a variety of applications, such as cellular base stations, satellite communication (SATCOM), and military radar. The down-conversion mixer is made up of...

Tunable/switchable devices are more and more required in modern communication systems. However, the realization of the tuning requires the presence of active devices, which in turn must be biased. The current paper comes up with a solution for designing and experimentally validating such a switchable Frequency Selective Surface. Two different metal...

A frequency selective surface consisting of a periodic copper pattern, built on a grounded FR4 substrate is introduced. The structure operates as an absorber for waves at 2.46 GHz, up to an incidence angle of 60o. Variation of the geometrical parameters allows for the modification of the working frequency, as also demonstrated by the parametric stu...

Periodic patterns printed on PCBs offer support for enhancement of 5G antennas performance in diversity, isolation, beam-forming and user tracking. Bulky wave processing devices such as dielectric lenses and reflectors can be replaced with such thin and cost-effective structures. These opportunities are addressed in the present chapter in connectio...

A frequency selective surface for spatial filtering in the standardized Ultra-Wide Band (UWB) frequency range is proposed. A very large stop-band of 1.75–15.44 GHz has been obtained, with good polarization insensitivity and an angular stability of more than 60∘ and more than 50∘ in TE and TM incidence, respectively. Circuit models have been devised...

A single metal layer, multifunctional frequency selective surface with a very simple pattern of the unit cell, containing a U-shaped metal resonator on FR4 substrate, and working in the low GHz frequency range is proposed. The structure realizes dual linear polarization filtering at frequencies of 1.83 and 4.14 GHz with fractional bandwidths of 34....

A double-layer frequency selective surface (FSS) built on FR4 substrate exhibiting two notch frequencies in the 0-10-GHz range is introduced. Recently published examples demonstrate that further research needs to be undergone for obtaining separate tuning of the resulted notch frequencies. Thus, this issue is addressed in this paper: the notch freq...

Electromagnetic compatibility (EMC) testing in automotive industry covers the following test methods: radiated emissions, conducted emissions, conducted and radiated immunity. CISPR 25 and ISO 11452 standards specify the procedures, equipment and frequency ranges used for EMC tests. In this paper, the activities and results obtained by the EMC team...

An electric vehicle (EV) uses an electric motor for traction and chemical batteries, superconductors, combustion cells and / or inertial masses as energy sources. To avoid problems regarding the accuracy of the mathematical model of the system, the use of artificial intelligence in electric drives is a viable alternative. Among other advantages of...

The paper describes a new real-time computation method named Mixt Profile of Speed (MPS), which is used to obtain the value of speed, at every sampling period of time, during the acceleration and deceleration stage, whereas the motion has three stages: 1) acceleration, 2) motion with imposed constant speed, and 3) deceleration. The method will dete...

Radiated immunity testing in the automotive industry is an activity with ever increasing importance. Immunity tests are being performed in the semi-anechoic chamber of the EMC laboratory, within Continental Automotive Romania. Testing results rely on measurements performed by operators and nominal parameters of the equipment involved, which are inp...

The radiated emissions measurement is one of the tests involved in Electromagnetic Compatibility testing. In this paper a measurement setup for radiated emissions from an automotive cluster is proposed. Assessment of correct operation of a device under test (DUT) according to the CISPR25 standard is reported. The test setup is based on measured dat...

The radiated immunity measurement is one of the tests that covers electromagnetic compatibility testing. The purpose of the paper is to investigate the performance of an automotive DUT test in the presence of an electromagnetic field inside a semi-anechoic chamber. The test complies with the ISO 11452-2 Standard.

The effects of geometry modulation applied to a periodic structure built in stripline technology are assessed by means of the dispersion diagrams calculated in the spectral, or k, plane by using a commercial electromagnetic eigenmode solver. Modifications of surfaces representing propagation modes, of electromagnetic band-gaps and of group velociti...

A 2D, volumetric (i.e., non-planar), structure consisting of two dielectric layers, loaded by various metal inclusions on multiple-periodic grids and closed by two confining metal planes is introduced in view of advanced dispersion engineering related applications. Full-wave simulation has been used to demonstrate that, for axial propagation, the s...

This paper deals with interference between digital transmission and various signals. We performed intentional interference to DVB-C and DVB-T real signals in order to evaluate the effect of a generic interferer over received BER. The chosen interferers were a FM signal and an analogic TV signal, superposed over the whole 8 MHz channel. We have exte...

This paper presents a study of voice command in industrial automation. Some tests were conducted on the voice recognition in a noisy environment. Compared to the laboratory environment, the signal was affected by the noise from different sources, such as: electrical motors, machine tools, human operators. An example with noise produced by an induct...

In order to evaluate the immunity of DVB signal to external interferer we made some measurements and comparisons between DVB-T signal and DVB-C signal of 8 MHz bandwidth subject to a FM interferer.

This paper presents a voice signal's noise reduction using adaptive / reconfigurable filters for ordering an industrial robot using isolated words. Finally, some results of the simulation are presented.

This paper presents a recognition method for ordering an industrial robot using isolated words, and also a method of speaker recognition, in case an order may be amended only by a particular person. Finally, some results of the simulation are presented.