SAW Filters

Image	Part Number	Description / PDF	Quantity	Rfq
	SF2419E RFMi	FILTER, SAW, 495 MHZ, 6SMD	0
	SF2425E RFMi	FILTER, SAW, 868.6 MHZ, 8SMD	0
	SF2423D RFMi	FILTER, SAW, 480 MHZ, 8SMD	0
	RF1439E RFMi	CRF,SM,315.000 MHZ	0
	SF2189A RFMi	FILTER, SAW, 140 MHZ, 12SMD	0
	SF2191E RFMi	FILTER, SAW, 1620.75 MHZ, 6SMD	0
	SF2380E RFMi	FILTER, SAW, 869.5 MHZ, 6SMD	0
	SF2437D RFMi	FILTER, SAW, 480 MHZ, 8SMD	0
	SF1081A-1 RFMi	FILTER, SAW, 71 MHZ, 10SMD	0
	RF3336C RFMi	CRF,SM,868.350 MHZ	0
	SF1186K-3 RFMi	FILTER, SAW, 1575.42 MHZ, 5SMD	0
	SF1140B-2 RFMi	FILTER, SAW, 75 MHZ, 10SMD	0
	SF2157A RFMi	FILTER, SAW, 156 MHZ, 12SMD	0
	RF1385D RFMi	CRF,SM,869.450 MHZ,	0
	SF2194E RFMi	FILTER, SAW, 1220 MHZ, 8SMD	0
	SF1183E RFMi	FILTER, SAW, 881.5 MHZ, 6SMD	0
	SF2315E RFMi	FILTER, SAW, 782 MHZ, 6SMD	0
	SF2250E RFMi	FILTER, SAW, 1615 MHZ, 6SMD	0
	SF2415E-1 RFMi	FILTER, SAW, 869 MHZ, 6SMD	0
	SF1143B-1 RFMi	FILTER, SAW, 315 MHZ, 10SMD	0

SAW Filters

1. Overview

Surface Acoustic Wave (SAW) filters are compact, cost-effective RF filtering components that utilize mechanical waves propagating along the surface of piezoelectric materials. By converting electrical signals to acoustic waves and back, SAW filters achieve precise frequency selection with steep roll-off characteristics. They play a critical role in modern communication systems by enabling spectral efficiency, noise suppression, and signal integrity maintenance in wireless devices, automotive electronics, and industrial equipment.

2. Main Types and Functional Classification

Type	Functional Characteristics	Application Examples
IDT-Structured SAW	Standard interdigital transducer design with <3 GHz operating range	Mobile phones, Wi-Fi routers
Dual-Mode SAW	Higher Q-factor through resonator coupling	5G NR frequency bands (n77/n78)
Temperature-Compensated SAW (TC-SAW)	0.5 ppm/ C stability using layered substrates	Automotive radar (76-81 GHz)
Miniature SAW (M-SAW)	0.5-2.0 mm package sizes for IoT devices	Bluetooth LE modules, wearables

3. Structure and Composition

Typical SAW filter construction includes:

Piezoelectric substrate (LiTaO3, LiNbO3, or quartz)
Aluminum interdigital transducer (IDT) electrodes (50-200 nm thickness)
Acoustic wave propagation path (10-100 wavelength)
Hermetic ceramic packaging with EMI shielding

Advanced variants incorporate temperature compensation layers (SiO2/Ta2O5) and reflector bars to enhance frequency stability and stopband attenuation.

4. Key Technical Specifications

Parameter	Description	Importance
Center Frequency (f0)	100 MHz - 6 GHz range	Determines application compatibility
Bandwidth (BW)	0.5-15% of f0	Impacts data rate capabilities
Insertion Loss	1.5-15 dB	Affects signal strength
Attenuation Slope	10-100 dB/MHz	Measures selectivity performance
Power Handling	100 mW - 5 W	Limits transmitter integration
Temperature Stability	50 ppm/ C (standard)	System reliability factor

5. Application Fields

Telecommunications: 5G base stations, CATV systems, GPS receivers
Automotive: Tire pressure monitoring systems (TPMS), V2X communication
Consumer Electronics: Smartphones, IoT modules, drones
Industrial: Medical imaging equipment, test & measurement instruments

6. Leading Manufacturers and Products

Manufacturer	Representative Product	Key Features
Murata Manufacturing	SAWF9BAF420M4A1	2.4 GHz WLAN filter, 0.9 dB loss
TDK Corporation	KC5030S108MB1	Sub-6 GHz 5G filter, 1.2 dB insertion loss
Skyworks Solutions	SAW-8851417	Multi-band cellular filter, 1.8-2.7 GHz
Infineon Technologies	B11243-F108	Automotive-grade TC-SAW for 80 GHz radar

7. Selection Recommendations

Key selection criteria:

Frequency match with < 0.1% tolerance
Temperature stability grade (standard vs TC-SAW)
Package size vs power handling requirements
Attenuation slope for adjacent channel rejection
RoHS compliance for environmental regulations

Example: For LTE Band 7 (2.6 GHz) applications, select TDK's KC5030S108MB1 with 110 MHz bandwidth and 1.2 dB loss in 0.5x0.5 mm package.

8. Industry Trends

Transition to 5G driving demand for 3-6 GHz SAW filters
Development of hybrid SAW-BAW modules for wideband applications
Miniaturization reaching 0.4x0.2 mm WLB packages
Advanced TC-SAW achieving < 10 ppm/ C stability
Integration with antenna switch modules (ASM) in SiP solutions