Arash Sadeghfam

• Dr.-Ing.
• FH Aachen

Der jüngst entwickelte Plasmajet vom Typ MiniJet-R in Kombination mit dem 2,45 GHz-Generator mit einer Ausgangsleistung bis zu 10 W bilden ein Kleingerät zur Erzeugung eines atmosphärischen Mikroplasmas. Das 2,45 GHz-Plasma im Argonstrom (nur 0,3 bis 1 sl/min.) ist kalt, da insbesondere im GHz-Bereich die leichten Elektronen und weniger die schwere...

High-intensity discharge lamps can be driven by radio-frequency signals in the ISM frequency band at 2.45 GHz, using a matching network to transform the impedance of the plasma to the source impedance. To achieve an optimal operating condition, a good characterization of the lamp in terms of radio frequency equivalent circuits under operating condi...

The invention relates to an HF system that comprises an HF device (5), particularly an HF lamp, as well an HF spark-plug or similar HF plasma application, and an HF signal-incoupling device (3) for operating said HF device (5). The HF system comprises an oscillator (7) for generating an HF signal to operate said HF device (5), and said system is ch...

The emergence of radio-frequency energy as a heat source in many new applications is becoming a reality, enabled by a new Generation of high-efficiency and high-power transistors. Klaus Werner, Program Manager at NXP Semiconductors, in conjunction with Prof. H. Heuermann and Dr. A. Sadeghfam at Heuermann Hochfrequenztechnik (HHF), uses the example...

This paper presents a microwave plasma (microplasma) ignition at 2.45GHz for spark plugs and other applications such as plasma beams as well as low and high pressure lamps. A novel transformation network is introduced, generating the very high voltage required for the ignition. Using this network, plasma ignition and sustainment are possible under...

This paper presents a fully digital transmitter architecture based on a digital polar modulator (DPM) and switch-mode power amplifier (SMPA). A simple method for comparison and estimation of different digital modulation techniques for SMPA is described. An estimation of the proposed digital polar modulator properties was done by means of a 2.1..2.2...

This paper presents a microplasma ignition at 2.45GHz for various applications as well as spark plugs, plasma beams, low and high pressure lamps by using a three stage impedance transformer. The presented transformation network generates a very high voltage. Using this network, plasma ignition and sustainment are possible under atmospheric press...

A matching network for matching an antenna to a transmitter or receiver comprises an input port for receiving high-fre quency power, an output port and a Switchable impedance transformation circuit, which is connected between the input port and the output port. The impedance transformation cir cuit comprises a CMOS switch in a high-frequency path,...

The present invention relates to an adjustable circuit for fil tering a transmission channel of an RFID signal and for Suppressing a carrier signal in the reception path between an input gate and an output gate, including at least one adjustable oscillator for generating an oscillator signal, at least one input mixing stage cooperating with the osc...

In this paper, an enhanced architecture for wide band data transfer based on a true differential modulation is presented, showing extremely high resistance against dispersion and fading due to multi-path propagation. The proposed system operates well with minor frequency stabilizing requirements and is characterized by a low part count. Since the m...

One of the most critical points in designing a RFID system based on the backscattering process is the limitations in the system dynamic resulting from the Tx-Rx-leakage, principally over the circulator and partly through environmental reflections. This signal can overshadow the modulated tag reply, which is generally at a maximum of only a few hund...

In this paper, a new concept for a software controlled phase shifter is presented. Hereby, a stable phase shift is realized for the locked loop output signal by digitally controlling the divider patterns of the SigmaDelta-modulator. In combination with a SigmaDelta-vector-signal-generator, it enables the realization of a purely software controlled...

The contemporary way to make telecommunication circuits is based on a differential approach, consisting of doubling the single-ended circuit. This results in a perfectly symmetrical structure with a doubled part count and twice the size. In this paper, a new design methodology based on coupled inductors is introduced, resulting in a part count for...

A monolithic integrated filter with mode conversion and impedance transformation for GSM 900 is presented. Hereby, a so called rat-race inductor is utilized, replacing up to six conventional inductors and one transformer, resulting in a reduction in chip size by approximately 50 %. The rat-race inductor is handled theoretically and 3D-EM based simu...

This paper presents the design methodology and results of a so-called balanced antenna, adapted from a new concept to realize a balun and 90-coupler, with two symmetrical antennas. The novel matching structure features invariant input-impedance for changing free space conditions and is broad-band matched. Using this circuit, isolators for UMTS-radi...

This paper presents a semiconductor balanced inductor for differentially driven systems, which reduces expensive circuit area by approximately 27 % and also achieves a Q-enhancement of over 25 %. The theoretical description for both the differential and the common modes are presented. Following 3D - EM simulations a differential 90° phase shifter a...