TR-916-SC-S Linx Technologies Inc, TR-916-SC-S Datasheet - Page 13

• Manufacturer Part Number: TR-916-SC-S
• Description: TRANSCEIVER RF 916MHZ 20PIN SMD
• Manufacturer: Linx Technologies Inc
• Series: SCr

Specifications of TR-916-SC-S

• Frequency: 916MHz
• Data Rate - Maximum: 33.6kbps
• Modulation Or Protocol: FM, FSK
• Applications: ISM, Garage Door Opener, Remote Controls, 2-way RKE
• Power - Output: -10dBm
• Sensitivity: -94dBm
• Voltage - Supply: 2.7 V ~ 13 V
• Current - Receiving: 15mA
• Current - Transmitting: 19mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Operating Temperature: 0°C ~ 70°C
• Package / Case: Module
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: TR916SCS

ANTENNA CONSIDERATIONS
GENERAL ANTENNA RULES
The choice of antennas is one of the most critical and often overlooked design
considerations. The range, performance, and legality of an RF link is critically
dependent upon the type of antenna employed. Proper design and matching of
an antenna is a complex task requiring sophisticated test equipment and a
strong background in the principles of RF propagation. While adequate antenna
performance can often be obtained by trial and error methods, you may also want to
consider utilizing a premade antenna from Linx. Our low-cost antenna line is
designed to ensure maximum performance and Part 15 compliance. The purpose of
the following sections is to give you a basic idea of some of the considerations
involved in the design and selection of antennas. For a more comprehensive
discussion please review Linx applications note #00500 “Antennas: Design,
Application, Performance”.
An antenna allows RF energy to be efficiently conveyed to and from free space. The
antenna
performance in the band of use and
capture as little as possible of other off-
frequency signals. It is important to
recognize that the antenna plays a
significant role in determining the
performance and legality of your end
product. In order to gain a better
understanding of the considerations
involved in the design and selection of
antennas, please review Linx applications
note
Application, Performance”.
It is usually best to utilize a basic quarter-wave whip for your initial concept
evaluation. Once your product is operating satisfactorily, a production antenna should
be selected to meet the cost, size and cosmetic requirements of the product.
Maximum antenna efficiency is always obtained when the antenna is at resonance.
If the antenna is too short, capacitive reactance is present; if it is too long, inductive
reactance will be present. The indicator of resonance is the minimum point in the
VSWR curve. You will see from the adjoining example that antenna (A) is resonant
at too low a frequency, indicating excessive length, while antenna (C) is resonant at
too high a frequency, indicating the antenna is too short. Antenna (B), however, is
“just right.”
Antenna resonance should not be confused with antenna impedance. The difference
between resonance and impedance is most easily understood by considering the
value of VSWR at its lowest point. The lowest point of VSWR indicates the antenna
is resonant, but the value of that low point is determined by the quality of the match
between the antenna, the transmission line, and the device to which it is attached.
To fully appreciate the importance of an antenna that is both resonant and matched
consider that an antenna with a VSWR of 1.5 will effectively transmit approximately
95% of its power while an antenna with a VSWR of 10 will only transmit about 30%.
#00500
should
“Antennas:
give
its
optimum
Design,
Figure 11
A
DESIRED FREQUENCY
B
C
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