Antonio Alves Ferreira, Jr.
 Write for Microwaves & RF
5 results found for Antonio Alves Ferreira, Jr., displaying items 1 - 5

November 2009   [Components]
Examine Balanced Twisted Bifilar Lines
Balanced twisted bifilar transmission lines have broad applications for any circuits in which impedance transformations are required. By using a vector network analyzer (VNA), it is possible to measure the characteristic impedance of these balanced transmission lines in order to design desired impedance transformations. Measurements with a VNA can be made by using a balancedunbalanced (balun) transformer that converts a balanced network to an unbalanced network. In...

April 2009   [Test & Measurement]
Evaluating Impedance Transformers With A VNA
Impedance transformers are widely used in radio communications applications to match the impedance of different devices and components to the 50- characteristic impedance of a high-frequency system. To evaluate the performance of an impedance transformer, a microwave vector network analyzer (VNA) can be used in such a way that measurement errors are minimized. Calibration procedures will be...

January 2008   [Test & Measurement]
Determine Twisted-Line Characteristic Impedance
This approach shows how to calculate and measure the characteristic impedance of balanced twisted bifilar transmission lines using a commercial vector network analyzer. ANTONIO ALVES FERREIRA JUNIOR Electronic and Electrotechnical Department National Telecommunications Institute (INATEL), 510 João de Camargo Ave. 37540-000, Santa Rita do Sapucaí, Minas Gerais, Brazil; e-mail: ...

March 2007   [Components]
Designing Wideband RF Impedance Transformers
Impedance matching devices are often used in high-frequency circuits, typically to match the impedance of a device or component to the characteristic impedance of a circuit or system. In some circuits, it is desirable for the impedance matching to achieve multiple-octave frequency coverage accompanied by low insertion loss. To help designers working with impedance transformations, this article explores the design of unbalanced-to-unbalanced (unun) wideband impedance...