Time Pressure Monitoring System (TPMS) Antenna Simulation with Ansys-EMIT - Part 3: Link Budget
Hello everyone, this is Daniel Esmaili. Today, I'm going to talk about calculating the link budget for a TPMS (Tire Pressure Monitoring System). This is the third part of a video series on simulating a TPMS antenna system.
Previous Parts Recap
In the last two parts, we discussed how we simulated the antenna with the rim and the car as a system. We studied the coupling between different antennas. Now, we are going to use those data from HFSS and transfer them to EMIT, another Ansys software, to calculate the link budget.
Introduction to EMIT
EMIT is a very useful tool for calculating link budgets and performing other post-processing tasks for our reports. You can use HFSS output or other software outputs and input the antenna results into EMIT. EMIT can accept inputs like S-parameters or far-field patterns. Alternatively, you can create these inputs within the software and study the link budget and other outputs.
Modulation Setup
Once you have your inputs, you need to assign or choose the modulation. For this simulation, we use BFSK (Binary Frequency Shift Keying), which is common in the car industry. BFSK uses two different frequencies to send a wave from point A to point B. If the frequency is F2, it indicates a '1', and if it's F1, it indicates a '0'.
BFSK Details
- BFSK stands for Binary Frequency Shift Keying.
- Uses two frequencies: F1 and F2.
- F2 represents a binary '1' and F1 represents a binary '0'.
- Commonly used in the car industry for its safety and simplicity.
Simulation Setup in EMIT
In EMIT, you need to:
- Import the antenna parameters and results.
- Locate the antennas by specifying their positions.
- Set the coupling and consider ground reflections in the simulation.
Simulation Parameters
- Modulation: BFSK
- Frequency Deviation: 0.005
- Slope: 3 (can choose 5 or 7)
- Bit Rate: 5000
- Channel Bandwidth: 0.25 MHz
- Power Peak: 40 dB
- Noise: -74 dB
- SNR: 50 dB
Simulation Results
With this setup, we ran the simulation and obtained the following results:
- Link Module without interference: 113
- Link Module with interference: -13
These results help in designing amplifiers and antennas, determining if an amplifier is needed.
Additional Results
- EMI Margin: 116
- Power at different frequencies was analyzed, focusing on the frequency of interest.
Conclusion
In summary, we imported the antenna coupling as an S-matrix, located the antennas, set different parameters, chose BFSK for modulation, and calculated the link budget. This process is highly recommended for similar applications.
About Ozen Engineering, Inc.
We at Ozen Engineering, Inc. use physics-based simulations to solve multidisciplinary engineering problems. If you have any questions or need consulting services, please feel free to reach out to us. We are a light channel partner for over 17 years, specializing in multi-physical finite element computation of fluid dynamics, as well as high and low-frequency electromagnetism. We offer both mechanical and electrical consulting.
Contact us at info@ozoneinc.com.
Thank you for watching this video, and have a great day!
Hello everyone, I'm Daniel Esmaili, and today I'm going to talk about calculating the link budget for a Time Pressure Monitoring System (TPMS) just like version monitoring system. This is the third part of a video series for simulating a TPMS antenna system.
In the last two parts, we simulated the antenna with the rim and with the car as a system, studying the coupling between different antennas. Today, we'll use data from HFSS and transfer them to EMIT, another ANSYS software, to calculate the link budget.
We'll discuss what PFSK is, the setup in EMIT, and the results. EMIT is a useful tool for calculating link budget and post-processing information for our report. You can use HFSS output or other software output and put the antenna results as S-parameter or Far field pattern as an input.
Alternatively, you can create them yourself inside the software and then study the link budget and other output. Once you do that, you need to assign or choose the modulation. For this simulation, we use BFSK, which I'll explain shortly.
We use the BFSK modulation, one of the most common in the car industry. Here's the TPMS system, with the T-MS and the valve stem, the circuit board, and antenna all here, located in each tire. In the center, you'll see the receiver antenna.
Four antennas, a sender around our four tires, and in the middle, we have the receiver antenna. That's how you see your tire pressure on your cluster. BFSK stands for binary frequency shift keying. It's a simple method using two different frequencies. If the frequency is F2, it goes faster.
If it's F1, it goes slower. If it's F2 and going faster, it's one. If it's F1 and going slower, it's zero. It's a common way of modulation and ensures safer transmission. Now that we know what BFSK is, let's set up the model.
In Emit, import the antenna parameters and results, locate them, set the coupling, and consider the ground as a reflection for our simulation. After positioning them, set the coupling and run the simulation.
For this simulation, we used binary FSK at V, a frequency deviation of 005, three slope, width rate 5000, channel bandwidth 025 megahertz, power peak 40dB, noise -74, and SRNR 50dB. With this setup, we ran the simulation, and here's the result.
We calculated the link margin, which is useful for designing our amplifier, antenna, or determining if there's no need for an amplifier. The power at the receiver, susceptibility, and peak in EMI margin are shown here.
In summary, we imported the antenna coupling as S-matrix, located the antenna, set different parameters, chose BFSK for our modulation, and calculated the link budget. We hope you enjoyed this video and found it useful.
If you have any questions or need consulting or service, please reach out to us at Ozen Engineering Corporation. We do mechanical and electrical consulting and multi-physical final element computation of fluid dynamics, high frequency and low frequency electromagnetism.
Thank you for watching, and have a great day.
