Amphenol 射频连接器介绍

Understanding RF and how it relates to cable and connectors
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.
Transmission Lines Impedance Frequency Range Return Loss-VSWR Insertion Loss Passive Intermodulation Distortion Power Handling-Voltage Isolation-Crosstalk RF Leakage Cable Assembly Amphenol RF Design Engineering Support and Capabilities
# 3. Frequency Range
Giga Mega Kilo Milli Micro Nano Pico = = = = = = = 1,000,000,000 1,000,000 1,000 1/1000 1/1,000,000 1/1,000,000,000 1/1,000,000,000,000 Billion Million Thousand One thousandth One millionth One billionth One trillionth
•Impedance
# 2. Impedance
# 2. Impedance
Impedance: The impedance of the connector generally must match that of the transmission line
Non-Constant
BNC Twinaxial UHF Twinaxial
•Planar
Transmission Line: Microstrip, Stripline, Coplanar waveguide are most common
# 1. Transmission Line
•Twin
Line- balanced line: two parallel conductors separated by a dielectric
# 3. Frequency Range
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If a frequency range is not specified, then the connector will be designed to catalog specs and this could cause the design process to take a lot longer
# 2. Impedance
Ohm’s Law
# 2. Impedance
•
What determines the Characteristic Impedance? • The ratio of Voltage to Current at any point in a transmission line • A transmission line can be represented as shown, with the values of C. L, R, and G determining the impedance
•Waveguide:
Rectangular, Circular
# 1. Transmission Line
•What
•A
is a transmission line?
transmission line is a conduit by which electromagnetic energy is transferred from one place to another
RF Made Simple
10 Basic RF questions that should be asked before helping a customer choose a connector However, first we should discuss • Why is it necessary to ask these questions? • Clear, specific information leads to quick, correct designs
# 1. Transmission Line
•
What is a transmission line?
•
A transmission line is a conduit by which electromagnetic energy is transferred from one place to another • Coaxial Cable- unbalanced: Center conductor surrounded by a concentric dielectric and outer conductor-Most popular type of transmission line • Also called the “RF line” when talking about connectors
Some Typical Frequencies:
House current 60 Hz in the US (50 Hz in many other countries) AM Radio 500 - 1500 kHz Shortwave Radio 10 MHz TV (channels 2-13) 60 - 250 MHz Cellular Phone 824 - 894 MHz Digital (PCS) Phone 1850 - 1990 MHz Satellite Radio 2.4 GHz Radar 6 - 26 GHz Direct Broadcast Satellite (DBS) 12 GHz
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Give as much information about the application of the connector to the design engineer as possible
• •
Is it used in a high power, narrow frequency band amplifier? Is it used in a band pass filter?
Impedance 50 Ohms 75 Ohms 50 Ohms
# 3. Frequency Range
•
• •
•
•
Frequency is the number of electromagnetic waves that pass a given point in 1 second Hertz is the unit of frequency measurement Generally, the RF performance of a connector degrades as the frequency is increased (c=λf) • Wavelength decreases, therefore smaller disruptions cause more problems Specifying the frequency will make it easier for the design engineer to optimize the performance Whenever possible, don’t specify a high frequency connector when a low frequency connector will work as well
50, 75 ohm
BNC SMB MCX 1.0/2.3 TNC
50 ohm
7/16 N,C, SC, HN Mini-UHF MMCX SMA
75 ohm
1.6/5.6 Type F Type G
Outer Diameter Inner Diameter Dielectric Constant .063 .063 .276 .020 .012 .120 2.0 2.0 1.0
•The
Impedance will help determine the connector series •Some series are only one impedance: C, SC, HN, 7-16 •Some series can be both 50 or 75 ohms: BNC, TNC, N
•
For example-A customer needs a new SMA to operate up to 12 Ghz. The catalog specifies 18 Ghz for SMA connectors. If the connector is optimized for 18 Ghz, it will likely take a lot longer than necessary to design. Also, more machining time may be necessary for compensation steps and more complex components.
Frequency Chart (GHz)
S M A (Hi P e rf.) S M A (S R ) S M A (F le x C o a x) N TNC 1.0/2.3 (Thre a de d) SMC 7/16 (C o a x, S R ) MCX MMCX 7/16 (C o rruga te d) 1.0/2.3 (P us h P ull) B NC SMB Type F Type G M ini-UHF 1.6/5.6 UHF Twina x B NC Twin
# 2. Impedance