Desenvolvimento de um filtro passa-faixas empregando tecnologia de ondas acusticas superficiais

AUTOR(ES)
DATA DE PUBLICAÇÃO

1997

RESUMO

The main objective of this work was to present the development of 70 MHz Bandpass filter, making use of Surface Acoustic Waves(SAW) technology. Some devices have been constructed in order to be used in the system to transmite TV signal by Fiberoptic, "TVFO". These devices were developed at the Brazilian Telecommunication Research an Development Centre (CPqDTelebrás), which provide alI condition to implement this work. Initially, the briefly discussion about the basic concepts used in SAW filter is presented and filters principIes of operation are analysed. Types of substrates utilized, method of excitation and detection of Surface Acoustic Wave by Interdigital Transducers (IDT), loss mechanisms in SAW devices and secondary effects are discussed. The design was done using Remez Exchange Algorithm and the SAW filters were developed using wet etch technology according to the facilities available at the CPqD-Telebrás laboratory. Finally, the SAW filters were characterized using HP 8753A NetWork Analyser. The results obtained in final measurements were considered as good, and the device was used in the TVFO system developed by CPqD-Telebrás. Design characteristics and typical results achieved in the final filter are: Center frequency 70 MHZ, 3 dB Bandwidth 26 MHz, Group delay ripple 30 ns, Insertion loss 38.8 dB and side lobes rejection greater than 28 dB, in LiNbO3 - YZ

ASSUNTO(S)

ondas acusticas superficiais filtros acusticos

ACESSO AO ARTIGO

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