SAW Filters

Image	Part Number	Description / PDF	Quantity	Rfq
	SF2249E RFMi	FILTER, SAW, 1602 MHZ, 8SMD	0
	SF2375E RFMi	FILTER, SAW, 1538.5 MHZ, 6SMD	0
	SF2183E RFMi	FILTER, SAW, 400 MHZ, 6SMD	0
	RF3619D RFMi	CRF,SM,404.000 MHZ	0
	SF2250E-1 RFMi	FILTER, SAW, 1615 MHZ, 6SMD	0
	SF2069A-2 RFMi	FILTER, SAW, 96 MHZ, 10SMD	0
	RF3605D RFMi	CRF,SM,372.000MHZ	0
	SF2049E RFMi	FILTER, SAW, 915 MHZ, 6SMD	0
	SF2197E RFMi	FILTER, SAW, 847 MHZ, 6SMD	0
	SF2238E RFMi	FILTER, SAW, 2650 MHZ, 6SMD	0
	SF2141B RFMi	FILTER, SAW, 210.38 MHZ, 10SMD	0
	SF2464E RFMi	FILTER, SAW, 400 MHZ, 6SMD	0
	SF2251E RFMi	FILTER, SAW, 1600 MHZ, 6SMD	0
	SF2214E RFMi	FILTER, SAW, 815 MHZ, 6SMD	0
	SF2321D RFMi	FILTER, SAW, 1090 MHZ, 6SMD	0
	SF2133E RFMi	FILTER, SAW, 1747.5 MHZ, 6SMD	0
	SF1142B RFMi	FILTER, SAW, 315 MHZ, 10SMD	0
	SF2137D RFMi	FILTER, SAW, 869 MHZ, 6SMD	0
	SF2193E RFMi	FILTER, SAW, 1228 MHZ, 8SMD	0
	SF2169E RFMi	FILTER, SAW, 1790.48 MHZ, 8SMD	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