AFS1842.5S4 Filters

Surface Acoustic Wave (SAW) filter technology has become a vital part of modern communication systems. It is a type of filter that is based on the propagation of acoustic waves on a piezoelectric surface due to the mechanical interaction between the electric field and the acoustic wave. SAW filters offer low insertion loss, high rejection attitude and sharp cuts. They are wide-band, low pass, band pass, high pass and notch filters. They can also be used in multiplexers and demultiplexers to combine and separate broadband signals.

The AFS1842.5S4 is a SAW filter used in the frequency band of 1842.5 MHz to 2050 MHz. It is intended for selective signal control and isolation in a wide range of applications. Its typical applications include mobile communication systems such as GSM, CDMA, WCDMA, LTE, GPS, and various satellite/spacecraft communications. It is also used in high power RF amplifiers, transfer switch modules, transceivers, receivers, transmitters, antennas, transponders, tracking systems, navigation systems, and satellite communications.

The AFS1842.5S4 is a surface acoustic wave (SAW) filter with a dual-mode structure. It features wide stopband rejection and sharp transition between passband and stopband, resulting in high-quality filtering. The center frequency is 1842.5MHz, band width from 1848MHz-2040MHz with a pass band ripple of 2dB. The stopband rejection is 30dB at 1848MHz to 2040MHz and 60dB at 1925MHz. The filter offers a low insertion loss, typically below 0.5dB and a fast turnaround time. It also operates with a low voltage of about 30V and consumes minimal power.

The AFS1842.5S4\'s working mechanism is based on surface acoustic wave (SAW) technology, which uses a piezoelectric substrate to generate acoustic waves. Acoustic waves are then propagated through the substrate via interaction between the electric field and the acoustic wave. This particular filter employs a stepped matching network with a series connection of inductor and capacitor to realize the transmission of the low-pass filter. A miniature device comprising two single-mode resonators, the GSM Double Wedge Step Resonator (DWSR), is utilized and placed in the center of the matching network. This resonator acts as both transmission and reflection paths for the filter, reducing the size and cost of the filter.

In summary, the AFS1842.5S4 is a SAW filter which is used for selective signal control and isolation between 1842.5MHz to 2050MHz. It offers a wide stopband rejection and sharp transition between the passband and stopband, thus providing excellent filtering. Its miniature design and fast turnaround time make it ideal for a variety of applications such as mobile communication systems and high power RF amplifiers.