|
|||
|
|
|||
|
From triquint.com
Stacked Crystal Filters, (SCF), are composed of multi-layers of piezoelectric and metal layers. Normally these filters have a complex frequency spectrum containing near-in spurious responses. However, by having the SCF formed in a Solidly Mounted Resonator (SMR) format, the performance of the device is greatly improved by the finite bandwidth of the SMR reflector. The conventional SCF also has a bandwidth that is too small for some wireless applications. This paper will describe the design and performance issues associated with stacked crystal filters using bulk wave thin films with aluminum nitride as the piezoelectric. Filters without spurious responses, filters having wide bandwidths, and filters operating at frequencies up to 8.5 GHz will be described in addition to GPS filters.
Stacked Crystal Filters, (SCF), are composed of multi-layers of piezoelectric and metal layers, as shown in Fig. 1b [1-3]. Normally these filters have a complex frequency response, shown in Figure 2, at approximate multiplies of the frequency corresponding to a half wavelength across the whole structure. The strong resonance is the one where there is a half wavelength across each of the piezoelectric resonators. The lower frequency response is at approximately half this frequency where there is a half wavelength across the whole structure. The upper frequency near-in spur occurs when there are three half-wavelengths across the entire structure.
Products & Services
Acousto-optic modulators are devices that use sound waves to modify the amplitude, frequency, or phase of light passing through an acousto-optic material.
Optical bandpass filters are designed to transmit a specific waveband. They are composed of many thin layers of dielectric materials, which have differing refractive indices to produce constructive and destructive interference in the transmitted light.
Passive filters are implemented using only passive components such as resistors, capacitors and inductors. These filters do not produce any amplification of the input signal.
Crystal filters are electronic filters that use monolithic crystals.
IC electronic filters are frequency-selective circuits that consist of devices such resistors, capacitors, inductors, transistors, or operational amplifiers coupled with reactive components.
Product Announcements
Topics of Interest
Wide bandwidth filters are of interest in current and emerging wireless and system applications for use in IF circuits or as front end filters. Filters for the new GPS M code and for wireless LAN are...
(Read More)
Coupled Resonator Filters (CRF) are a new form of bulk acoustic wave device that involves the vertical stacking of resonators. In that regard, the CRF can be thought of as a variation on the better...
(Read More)
Resonator and filter evolution Drivers Higher frequencies and wider bandwidth data Lower cost for increasingly sophisticated RF systems Advances in ICs Responses Direct conversion chip sets High...
(Read More)
Abstract Coupled Resonator Filters (CRF) are a new form of bulk acoustic wave device that involves the vertical stacking of resonators. In that regard, the CRF can be thought of as a variation on the...
(Read More)
Thin film resonators have been made that exhibit a high degree of temperature compensation. These resonators are composed of piezoelectric aluminum nitride films, aluminum top and bottom electrodes,...
(Read More)
Technical Articles
|
|