(1) The student developed an electronically controlled RF coil for magnetic resonance spectroscopy that can be tuned and matched at any frequency between 80-115 MHz through two control voltages. The coil is approximately 0.5-1 cm3 in volume. (2) Through designing circuit schematics and printed circuit boards, the student created a coil that can be tuned and matched electronically using varactor diodes and PIN diodes controlled by a digital/analog interface. Testing showed the coil meets the specifications. (3) The student spent 25 hours in meetings with their supervisor, 100 hours on laboratory work, 25 hours on readings, and 15 hours writing reports, for a total of 165 hours or 6.

1. Absender
Ao. Univ.-Prof. DI Dr. Hermann
Scharfetter
hermann.scharfetter@tugraz.at
Tel. +43(0)316 873-7394
Fax +43(0)316 873-7890
Sekretariat:+43(0)316 873-7391
daniela.agrinz@tugraz.at
http://www.imt.tugraz.at
INSTITUT FÜR MEDIZINTECHNIK
A – 8010 Graz, Kronesgasse 5
Leiter: Univ.-Prof. Dipl.-Ing. Dr. R. Stollberger
DVR: 008 1833 UID: ATU 574 77 929
To
Technical University of Sofia
Graz, 17.Juli 2014
Confirmation
Name of the student: Dinyo Ivanov
Student registration number (Matr.Nr.): 1332039
Name of supervisor: ao. Univ.-Prof. DI Dr. techn. Hermann Scharfetter
Title of thesis/project: Development of an electronically controlled wideband RF coil
for magnetic resonance spectroscopy
Mr. Ivanov was working on the above mentioned thesis/project at the Institute of
Medical Engineering at Graz University of Technology from 15-05-2014 until 17-07-
2014.
(1) Topic/didactic goal:
The topic of the project was to develop a special receive coil for wideband nuclear
magnetic resonance spectroscopy with the following requirements: The coil must
have a volume of about 0.5 - 1 cm3
and must be tuned and matched at any
frequency within a specified range, e. g. 80 – 115 MHz. The tuning and matching
should be controlled electronically by two voltages which are provided by an existing
autocalibration interface. During transmit the coil must be protected by swtitching it
off via PIN-diodes. The student learned to understand the mechanisms of high-
frequency circuit design and the working principles of RF coils for magnetic
resonance experiments. He also learned to consider parasitic effects which can
adversely affect the performance of these circuits
(2) Specifications and Results:
The Student developed several types of schematics and printed circuit layouts in the
process of in the development and improvement of the tuning/matching and

2. protection circuitry. He personally soldered, tested and improved the design with the
aid of modern RF equipment such as a network analyzer.
During the work on this project Mr. Ivanov learned how to create a tuned and
matched RF coil in the VHF range (around 100 MHz) and how to control the tuning
and matching capacitances in different ways. First he learned how to adjust the
circuitry manually with trimming capacitors and then he employed varactor diodes
and PIN-diodes so as to control the RF behaviour of the coil via a digital/analog
interface. The resulting circuit matches the specifications given by the supervisor
and can be integrated into a custom-built research spectrometer.
(3) Workload:
Workload in hours
Contact hours with supervisor 25
Laboratory work 100
Reading assignments 25
Writing reports 15
Total 165
The workload for the thesis/project work equals 6.5 ECTS Credits.
(4) Assessment:
Mr. Ivanov was given the Austrian grade sehr gut (1) - excellent for his/her work.
Graz, 17-07-2014
Place & Date Signature of the supervisor
Ao. Univ.-Prof. Dipl.-Ing. Dr. Hermann
Scharfetter
Stamp: