RF Filters

Part Number	Description / PDF	Quantity
2450LP14A100T Johanson Technology	RF FILTER LOW PASS 2.45GHZ 0603	1360
3600BP14M0600T Johanson Technology	RF FILTER BAND PASS 3.5GHZ 0603	127
1810LP14A200T Johanson Technology	RF FILTER LOW PASS 1.81GHZ 0603	2
2450LP15A050E Johanson Technology	RF FILTER LOW PASS 2.45GHZ 0805	0
5550BP14A0800T Johanson Technology	RF FILTER BAND PASS 5.55GHZ 0603	1696
1000LP41B1000E Johanson Technology	RF FILTER BANDPASS 911.5MHZ 1210	1730
5515BP15C725E Johanson Technology	RF FILTER BAND PASS 5.5GHZ 0805	664
5515LP15A730E Johanson Technology	RF FILTER LOW PASS 5.5GHZ 0805	117
1748LP18A075E Johanson Technology	RF FILTER LOW PASS 1.748GHZ 1206	17206
2500BP15M400E Johanson Technology	RF FILTER BAND PASS 2.5GHZ 0805	3620
2450BP08A0100T Johanson Technology	RF FILTER BAND PASS 2.45GHZ 5SMD	0
2450HP14A100T Johanson Technology	FILTER HIGHPASS 2.4GHZ WIFI	0
0915LP15B026E Johanson Technology	RF FILTER LOW PASS 915MHZ 0805	36396
2450BP15E0100E Johanson Technology	RF FILTER BAND PASS 2.45GHZ 0805	24870
0900LP15B0063E Johanson Technology	RF FILTER LOW PASS 911.5MHZ 0805	0
2450BP07A0100T Johanson Technology	RF FILTER BAND PASS 2.45GHZ 0402	16596
5515BP15B975E Johanson Technology	RF FILTER BAND PASS 5.5GHZ 0805	6598
2450LP15B050E Johanson Technology	RF FILTER LOW PASS 2.45GHZ 0805	0
2450LP14B100T Johanson Technology	RF FILTER LOW PASS 2.45GHZ 0603	30878
5130BP18U4060E Johanson Technology	RF FILTER BAND PASS 5.13GHZ 1206	0

RF Filters

1. Overview

RF Filters are passive components that selectively allow or block specific frequency ranges in radio frequency (RF) systems. They are critical for signal integrity in wireless communication by eliminating interference, enhancing signal clarity, and ensuring compliance with regulatory standards. Modern applications include 5G networks, Wi-Fi systems, radar, and IoT devices.

2. Main Types and Functional Classification

Type	Functional Characteristics	Application Examples
Bandpass Filter	Allows frequencies within a specific range	Cellular base stations, Wi-Fi routers
Low-pass Filter	Passes frequencies below cutoff frequency	Power amplifiers, GPS systems
High-pass Filter	Attenuates frequencies below cutoff frequency	Satellite communication systems
Band-reject Filter	Blocks specific frequency bands	Medical imaging equipment
SAW Filter	Uses surface acoustic waves for precise filtering	Smartphones, automotive radar
BAW Filter	Employs bulk acoustic resonators for high-frequency operation	5G mmWave devices, WLAN modules
Cavity Filter	Metallic resonant cavities for high Q-factor	Radio astronomy, military communication

3. Structure and Components

Typical RF filter structures include:

Resonant Elements: Determine passband frequencies (e.g., quartz crystals in SAW filters)
Transmission Lines: Microstrip or coplanar waveguides for signal propagation
Dielectric Materials: Substrates like alumina or LTCC for impedance control
Enclosure: Metal housing for EMI shielding (cavity filters) or surface-mount packages
Ports: Input/output connectors (SMA, N-type) or PCB pads

Advanced designs integrate MEMS tuning mechanisms or LTCC multilayer structures for miniaturization.

4. Key Technical Specifications

Parameter	Description	Importance
Frequency Range	Operational bandwidth (e.g., 2.4-2.5 GHz)	Determines application compatibility
Insertion Loss	Signal attenuation in passband (e.g., <1.5 dB)	Impacts system sensitivity
Bandwidth (3dB)	Passband width at half-power points	Defines frequency selectivity
Rejection Ratio	Stopband attenuation level (e.g., >40 dB)	Interference suppression capability
Power Handling	Maximum input power (e.g., 20W CW)	Prevents component damage
Temperature Stability	Frequency drift vs temperature (e.g., 50 ppm/ C)	Ensures operational reliability

5. Application Fields

Telecommunications: 5G NR base stations, fiber optic networks
Aerospace: Avionics navigation systems, satellite transponders
Medical: MRI RF coils, ultrasound imaging equipment
Automotive: V2X communication modules, 77GHz radar systems
Industrial: Wireless sensor networks, RFID readers

6. Leading Manufacturers and Products

Manufacturer	Representative Product	Key Features
Murata Manufacturing	SAWLF5G30D	3.3-4.2 GHz BAW filter for 5G
Qorvo	QPM2515	2.3-2.7 GHz bandpass filter, 100W power rating
Skyworks Solutions	SKY13460	DC-6 GHz SPDT switch with integrated filters
Mini-Circuits	BFCN-1100+	Cavity filter with 1050-1300 MHz range
TE Connectivity	RFHF35-2.92M	High-frequency coaxial filter up to 40 GHz

7. Selection Guidelines

Key considerations:

Frequency Requirements: Match passband with system operating bands
Power Handling: Ensure ratings exceed maximum system power
Environmental Conditions: Temperature (-40 to +85 C), humidity resistance
Form Factor: SMD for compact designs vs. coaxial for high-power applications
Cost vs. Performance: Trade-off between ceramic filters (low-cost) and cavity filters (high-stability)

Case Study: Selecting a BAW filter for 5G mmWave devices requires <0.5 dB insertion loss, 28 GHz operation, and compliance with 3GPP TS 38.141-1 standards.

8. Industry Trends and Future Outlook

Key development trends:

Higher Frequency Operation: mmWave filters for 5G/6G (24-100 GHz) using photonic bandgap structures
Miniaturization: Wafer-level packaging reducing SAW filter size to 0.4x0.2 mm
Integrated Solutions: Filter+LNA modules for IoT devices (e.g., Qorvo's QM33013)
Advanced Materials: Lithium niobate on silicon (LiNoSi) substrates improving temperature stability
Software-Defined Radio: Tunable RF filters with MEMS or ferroelectric materials

The market is projected to grow at 9.8% CAGR (2023-2030), driven by automotive radar and satellite internet demand.