SAW filters for Global Positioning Satellite (GPS) receivers

SAW sensor for fastener failure detection

“…The vector analyzer excites the SAW device across a frequency range and simultaneously measures the S parameters, specifically the reflection coefficient S 11 . The programmable features of the network analyzer were used to setup a small frequency range, and then to locate a specific amplitude level of -13.9 db.…”

“…Langasite does not have any phase transitions lower than its melting point, therefore it does not lose its piezoelectric properties until 1470 °C [10]. SAW devices operate down to cryogenic temperatures (77 ºK) as well [11]. SAW devices are also inherently radiation hardened up to 10 MRads, so ionizing radiation is not a concern [12].…”

Design Enhancement of Miniature Lumped-Element LTCC Bandpass Filters

“…The primary challenge involved in designing a 1.5-GHz GPS filter is successfully realizing the very narrow Manuscript fractional bandwidth, typically less than 5%. The traditional solution has been to use bulky acoustic wave filters [2], [3] or combline filters [4]. Recently, lumped-element low-temperature co-fired ceramic (LTCC) filters have been designed for applications other than GPS [5]- [7].…”

Methods and design techniques for the miniaturization of an L-band System-on-Package receiver front-end

“…The primary challenge involved in designing an L-band GPS filter is successfully realizing the very narrow fractional bandwidth, typically less than 5%. The traditional solution has been to use bulky acoustic wave filters [24], [25], or combline filters [26].…”

“…Unfortunately, in heterodyne receivers, an undesired band that is symmetrically located on the other side of the LO frequency (JLO = IRF + fiF in this case) is also downconverted. This undesired band is commonly called the image and presents a 25 serious problem due to the fact that it is downconverted on top of the desired signal.…”