Mehmet Cinar

A new design for calculable resistor

UME has improved a coaxial and bifilar type of resistors that have been widely used for determining of the resistance unit from DC to up to several kHz at many primary laboratories. This paper describes the modeling, construction and measurement results of the calculable resistors, which are specially designed in order to eliminate the effects of vibration and mechanical shocks during transportation, at a nominal value of 1 k/spl Omega/, 10 k/spl Omega/ and 12,906 k/spl Omega/.

Alternative conducted emission measurements on mains without LISNs

Conducted emission tests are always performed by the use of LISNs in laboratories in accordance with CISPR22, CISPR11 and other similar standards. However, it is not always possible to use LISNs because of some limitations. If the EUT (Equipment Under Test) has large dimensions or high currents, it is not, for most of the time, possible to send it to an EMC laboratory or to use LISNs during the test. As a consequence, usage or development of alternative conducted emission test methods is inevitable in industry. In this paper, we made conducted measurements on actual EUTs in alternative environments whose impedances are different from the standard LISN impedance and continued to establish the fundamentals of alternative conducted emission tests based on the impedance measurements of the EUT, supply and used cables. We also established the correlation, on the basis of impedance measurements, between these alternative conducted emission test method and the reference conducted emission test method.

Effects of sensor positions on military radiated susceptibility tests

The MIL-STD 461F RS103 test is one of the essential radiated immunity tests for military equipment. Unlike the pre-calibration method of commercial radiated immunity tests such as EN61000-4-3, the RS103 test requires the placement of an electrical field sensor close to the application point of the EUT (Equipment Under Test) and also requires active-leveling of the field based on the feedback from the sensor without use of a pre-calibrated field. In most cases, the position of the sensor is not certain in the standard and every laboratory uses their own selections for probe positions which are close to the application region. In this research, we showed that the chosen sensor position directly affects the value of power injected into the antenna, consequently affects the test results significantly for a constant electrical field value owing to the reflections coming from the EUT itself.

Influence of dielectric support on military radiated emission tests above 30 MHz

We experimentally investigated the influence of dielectric supports used on RE102 radiated emission tests of the MIL-STD-461F EMC standard for table-top and conductive surface mounted Equipment Under Test (EUT). A variety of dielectric materials which are commonly selected as supports under EUT cables in RE102 tests were investigated by using an actual RE102 test setup in a semi anechoic chamber. Each investigated material yielded different effects on RE102 test results in comparison to the case without support, in other words, with the air support.

Loop antenna pattern measurements

In this study, we installed a loop antenna pattern measurement system and investigated the radiation patterns of loop antennas, which has not been adequately investigated so far in literature. The loop antenna pattern measurements were realized in two modes, receiving and transmitting modes. During pattern measurement, the loop antenna under measurement was rotated from 0° to 360° for azimuth plane and from 0° to 180° for elevation plane by suitable steps and consequently, two-dimensional and three-dimensional patterns of the antenna were drawn. 3-dB beamwidths of the loop antenna were calculated by using the pattern data and the importance of beamwidth was emphasized in terms of EMC tests and measurements in azimuth and elevation plane. In addition, directivity values of the antenna were calculated with the assumption of far field by analyzing all the pattern data obtained from the measurements.

Fabrication of 10 mΩ/10 A DC current shunt at UME

In this study, it is aimed to fabricate DC current shunt in the range from 1 A to 10 A with high accuracy and low drift. Resistance value of shunt was chosen as 10 mΩ which is compatible to the national traceability chain. 10 mΩ DC current shunt was fabricated, characterized and was put into use at TÜBİTAK UME (National Metrology Institute of Turkey) DC Resistance Laboratory.