OBD Wireless Transceiver Model – with outer sleeve removed. Figure 1.
New LDS Technology gives Taoglas a highly competitive edge in offering ultimate design freedom for customers. We support running design changes such as antenna performance tuning & optimisation as seen in our SmartWatch case study. With Taoglas working closely with the customer during all stages of the design process, we can facilitate a high degree of design flexibility. See how we use LDS technology to provide innovative solutions for the Automotive industry.
On-Board Diagnostics [OBD] Wireless Transceiver Module.
Integrate a high-performance GPS and a GSM antenna into compact OBD form factor.
The challenge was to integrate two high performance and efficient antennas into the compact space provided. The first antenna was a 1575.42 MHz GPS antenna to be used for positioning information, the second antenna would be a dual-band GSM antenna for data transmission and designed to operate at both 900MHZ and 1800MHz. The first stage of the design involved working closely with the customer to mechanically model the product in Solidworks®. This stage of development was important as the 3D structure, the construction requirements and space limitations needed to be clearly defined. Taoglas is now offering LDS Technology to address customer needs for smaller, higher performance products with integrated LDS antennas.
Once the physical outline and space requirements were complete, the choice of LDS polymer resin could be made. Based on the requirements of the application, ABS resin was chosen as it is a popular polymer, for internal cabin use, in the automotive industry. Many LDS resins* are available within the popular LDS resin families shown below.
- Polycarbonate (PC)
- Acrylonitrile Butadiene Styrene (ABS)
- Polypropylene (PP)
- Nylon (PPA)
- Polyethylene Terephthalate (PET)
- Polybutylene Terephthalate (PBT)
- Polyphenylene Sulphide (PPS)
- Liquid Crystal Polymers (LCP)
Once the physical design and LDS resin had been selected, the basic antenna designs could begin. The two antennas were placed on opposite sides, and on the outer surface, of the planned plastic housing. The positions of the antennas were chosen to maximise isolation between antennas themselves and between the antennas and from the main internal electronics board [PCB].
The design of the connections to both antennas was achieved by using compact surface mount “C” clips. These connector components are supplied by Taoglas [part number CC.001] and are ideal for use in these types of compact assemblies. They are easy to assemble onto the main PCB as they use the same standard SMT assembly process used to manufacture the PCB.
The plastic housing design is also optimised to provide dedicated contact points for the clips to make reliable connections to the LDS pattern. The LDS pattern is designed so the contact points will be directly over the PCB mounted “C” clips during final assembly (see figure 2). The “C” themselves have a working vertical tolerance of 1mm so possible concerns with construction tolerances are not an issue.
(Cut away graphic showing two CC.001 clips connecting with the GPS antenna pattern) Figure 2
Finally, detailed modeling of the two antennas could be completed with the final physical requirements defined. For full antenna modeling, Taoglas uses CST Microwave Studio®. The antenna performance was iterated on and optimised using CST minimising the need for expense and time consuming “trial and error” sample builds.
The first production representation samples of the device were manufactured using the Taoglas LDS capability in Taiwan. A MicroLine 160i LDS laser was quickly configured to precisely transfer the antenna pattern from CAD data onto the surface of the first molded housings. Subsequent metalization of the antenna surfaces, activated by the LDS laser, provides plating Copper plated to a thickness of 12um followed by Nickel plated to a thickness of 4um.
(Optimised CST Electromagnetic field and current models) Figure 3
(LPKF Microline 160i LDS Laser available at Taoglas Taiwan) Figure 4
For the customer, Taoglas provided two highly integrated and efficient antennas which performed well within their compact OBD transceiver device. The LDS solution easily outperformed traditional approaches. The radiation patterns for traditional antennas such as stamped metal, PCB mount or integrated PCB antennas would have been impacted by their close proximity to the main electronics PCB and would have led to reduced isolation between antennas. The alternative was to make the OBD transceiver module bigger which was not an option for the customer. Finally, LDS allowed the antenna patterns and associated performance to be optimised quickly, without expensive tooling modifications, and allowed the product to go quickly into production.
Read more about Taoglas LDS Technology
- Solidworks® and CST Microwave Studio® Registered trademarks of Dassault Systèmes, France.
- MicroLine 160i is an LDS laser system manufactured and licensed by LPKF, Germany.
- CC.001 is a SMT “C” Clip available from Taoglas: http://www.taoglas.com/product/cc-001-smt-c-clip-connector/
- *: LPKF LDS Approved Polymer Resins: http://www.lpkf.com/_mediafiles/2074-approved-plastics-lpkf-lds-2017-02.pdf
- **: LPKF LDS Design Guidelines: http://www.lpkf.com/applications/mid/design-rules/index.htm
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