Sensor iD ST25RU3993 Development Boards Instruction Manual
- June 13, 2024
- Sensor Id
Table of Contents
SENSOR ID SRL
P.Iva / C.F. N. 01614260709
Reg. Imp. N. 01614260709
SEDE LEGALE
Corso Amatuzio N. 122
86021 – Bojano – (CB) – Italy
SEDE OPERATIVA
Via G. Mucciardi N.5 – 86020
Campochiaro – (CB) – Italy
RFID OPERATIONAL DESCRIPTION MANUAL
Product:|
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Document type:| Operational description manual
Confidentiality:|
Document Rev.
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Date
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Author
0.1
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13/01/2023
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I. Product description
The RFID technology operates in the 860-960 MHz UHF band, so the reader is
configured at the factory to operate within the specific band of each region.
RFID UHF bandwidth in North America ranges from 902.5 to 927.5 MHz.
- RFID BOARD: RF circuit based on the integrated reader ST25RU3993 device, controlled by BGM13S32A and an antenna UHF RFID Reader
- 5V DC POWER SUPPLY
RFID BOARD INTEGRATED ON THE PRODUCT PCB
RFID OPERATIONAL DESCRIPTION USING A FLOWCHART
2 RF circuit
The core component of the RF circuit is the ST25RU3993 chip. It receives digital base-ban transmit data and commands from the MCU via the SPI interface. ST25RU3993 frames the transmitted data accordingly, and automatically encodes it into PIE symbols. Based on the PIE encoded symbols ST25RU3993 creates a sinusoidal shaped modulation signal. The modulation signal can either be ASK or PR-ASK. ST25RU3993 synthesizes an RF carrier frequency with a VCO / integer-n phase locked loop (PLL). The frequency reference for the PLL is a temperature compensated crystal oscillator (TCXO).
The carrier frequency is modulated by the ASK or PR-ASK shaped modulation signal. The ST25RU3993 differential output is connected to a 2:1 balun where the transmit signal is transformed from a 100 Ω differential to a 50 Ω single- ended signal. In order to limit cross channel a SAW filter must be placed on the TX-path of the reader, the selected SAW filter is B3717 which is manufactured by TDK.
The signal then proceeds to the external power amplifier to generate a high-
power output signal with approximately 30 dBm in the default configuration of
the board. The output of external power amplifier is connected to a low-pass
filter, which attenuates the second and third harmonic of the carrier
frequency.
The filtered transmit signal to directional coupler, which has a coupling
factor of 10 dB. The purpose of this device is to isolate the transmit signal
from the receiving inputs of ST25RU3993 and has a major influence on the
sensitivity of the reader. The isolated port of the main directional coupler
is connected to a 2:1 balun to transform the incoming tag response signal to a
100 Ω differential signal that is connected to the receiving pins of
ST25RU3993
3 Antenna matching
To maintain the sensitivity of the reader the self-jamming signal reaching the receiving inputs of ST25RU3993 needs to be minimized. The self-jamming signal comprises reflections from the antenna and the leakage across the main directional coupler. To minimize the self-jamming signal a carrier cancellation circuit is connected to the coupled port of the main directional coupler.
The antenna matching circuit can change its impedance and hence to reflect a certain amount of the coupled power back into the directional coupler. This reflected signal is combined with the self- jamming signal at the isolated port of the main directional coupler.
To find the impedance setting of the antenna matching circuit resulting from a self-jamming signal cancellation the power of the self-jamming signal needs to be measured. Such a measurement capability is provided by ST25RU3993 and is referred to as reflected power measurement. An optimal impedance setting of the antenna matching circuit results in low reflected power. The main components of the antenna matching circuit are two digital tunable capacitors, which are controlled by the microcontroller via the SPI interface. The fixed lumped components of the antenna matching circuit help to center its impedance to 50 Ω and define the impedance step created by one change of a digital tunable capacitor.
4 Antenna specifications
Electrical
Frequency|
915 MHz
Return Loss
| -10dB max.
Efficiency|
77.1 %
Average Gain
| -1.13 dB
Peak Gain|
2.51 dBi typ.
Axial Ratio
| 3.0 max (d) Zenith
Polarization|
RHCP
Impedance
| 50
Mechanical
Dimensions
| 35 x 35 x 6 mm
Material|
Ceramic
Pin Diameter
| 0.9 mm
Pin Length|
2.4 mm
Weight
| 34.3 g
Environmental
Operation Temperature
| -40°C to 85°C
Storage Temperature|
-40°C to 105°C
Humidity
|
Non-condensing 65°C 95% RH
- Antenna properties were measured with the antenna mounted on 70*70mm Ground Plane
Antenna Characteristics
Return Loss Peak Gain
Efficiency Average Gain
RADIATION PATTERN
4.2 X-Y Plane
X-Z Plane
Y-Z Plane
+39 0874.775257 [email protected]
WWW.SENSORID.IT
[email protected]
Registro AEE N. IT 2203000013700 Azienda certificata ISO 13485:2016
Reg. Pile ed Accumulatori N. IT 20010P00005962 Azienda Certificata ISO
9001:2015
Documents / Resources
|
Sensor iD ST25RU3993 Development
Boards
[pdf] Instruction Manual
U27BTW11, 2AVDNU27BTW11, 2AVDNU27BTW11, ST25RU3993 Development Boards,
Development Boards, Boards
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