The goal of our modeling program is to equip a signal integrity group with unimpeachable 3D EM models and material properties that achieves less than 2 Ohms measure-based TDR to simulation and Extreme Signal Integrity performance and a 2% impedance tolerance for Stripline transmission lines (WRT has a process to exceed the 5% even for multi-laminate construction).
Material Identification Program
WRT has a highly proprietary material ID methodology, using a host of structures that are used to fit material ID in X-Y and Z PCB orientation. There is both a model-based pre-fabrication and measure-based post-verification phase built into each program. Our material Identification and modeling is EDA-centric, fitting the models in 3D electromagnetic (EM) simulation software.
Construction of a reduced size Channel Modeling Platform (CMP) that focuses solely on material ID is core to this activity. There is a partial set of verification structures that are used to verify the models.
In the post-fabrication phase, measurements of the CMP undergo comprehensive S-parameter quality checks which proceeds careful calibration. Cross-sectional analysis using a PCB test strip included with each CMP is also done, as well as PCB fabrication verification.
Measurements, comprehensive model material ID fit reports, PCB libraries of the CMP, and measurement to simulation examples are included in each final report.
See part of an example report here.
2D, 2.5D, and 3D Simulations to 90 GHz
The Material Identification program is a pre-requisite of this service activity if WRT has not designed with laminate system. We can discuss this in first meeting.
- Modeling using Ansys HFSS (3D), Simbeor (2 and 2.5D)
- Optimization of via (SE and DIFF), breakouts, edge launches, etc
- Model verification from vendor (ELF launch, VLF launch, backplane connector EDA model verification)
- Simulated to Measured Correspondence Program and Report
See examples of EDA optimization here.
WRT helps our customers develop test fixtures and any related designs requiring Extreme Signal Integrity (ESI). See the WRT FAQ for a full explanation of ESI.
See examples of successful test fixture designs here.
Here is our typical engagement with Customers:
Step 1: Initial Collaborative Discussion for Custom Test Fixture Design
Contact WRT sales by email at firstname.lastname@example.org or by phone at 1-800-604-0858 to arrange a web-based meeting to discuss your requirements with the WRT ESI Team:
- Prior to the meeting we will typically establish a mutual NDA. Send email to email@example.com to commence this process.
- Please be prepared to discuss the high-level objectives, rough schedule, what level of future-proofing is required, and ancillary requirements (cost, production volume, mechanical or thermal requirements, etc.).
- We also like to identify the level of signal integrity challenge, operating bandwidth, rise/fall times, signal integrity margins, etc. If you do not know this, WRT will help you since these metrics are not always straightforward.
Step 2: Generate Initial Statement of Work and Budgetary Quote
After the first meeting a small team will be set up to drive towards a customer Statement of Work (SOW), assisted by Jim Bell at WRT. The SOW typically contains:
- General information regarding the project, high-level description, customer team
- The high-level objects of the project bulleted out in greater detail
- What customer expects for high-level deliverables from WRT
- Level of collaboration between WRT/Customer
- Proposed schedule and milestones
Based on the preliminary SOW, WRT often provides a rough budgetary quote. At this stage we
- Generatedetailed list of milestones and deliverables from customer list
- Give an estimated cost to complete each milestone
- Tabulate a rough time interval to complete each milestone including concurrency
- Often identify and discuss crux technical issues and mitigation
Once the final SOW is accepted by both parties, WRT will generate a formal quote.
Step 3: Purchase Order Acceptance and Project Begins
WRT Quote acceptance is official once a Purchase Order is received. Once the project begins
- WRT is paid on successful completion of milestones. Each milestone is clearly defined in the formal quote.
- Customer management formally signs off on each milestone completion before WRT invoices
Project and Technical Management
- Typically, there is an engineering team meeting once/week or every two weeks
Team meetings include project management tracking of milestones and discussion of crux technical elements.
WRT provides a wide range of PCB design services, including Schematic capture, PCB layout and PCB board procurement. We Support Cadence Allegro/OrCad PCB Designer and Capture CIS. We also offer complete solutions for PCB fabrication, assembly and validation to our customers.
Typical Project management by WRT staff includes
- Supervision of and first contact for board design engineer
- Periodic board design checks as sections are completed
- Conduct board placement and post-layout reviews with Customer
- Weekly status reports to Customer
- Identify team, responsibilities
- Set up secure shared file folder (i.e. Sharefile)
- Review customer design objectives and deliverables (overall function, high-speed design, data rate, max frequency, return loss margins, overall signal integrity)
- Review design timing constraints
- Review initial PCB Placement (Visio mock-up)
- Identification of signal integrity issues
- Risk ID and mitigation strategies, design trade-offs
- Establish schedule, milestones with customer
- Coordinate PCB Symbol Library generation
- Timing constraint set up
- Placement design review w/ customer
- Standard Routing (nets with no timing constraints)
- Balance Routing (nets with timing constraints)
- Critical Design Review
- Post Processing (Create Fab package)
- Deliver Fab Package to fabricator
WRT has 67 GHz VNA measurement capability along with 11 psec Tektronix TDR capability. WRT provides VNA S-parameter training either on-site or virtually (GoPro Camera is used at customer site). Email firstname.lastname@example.org or call 1-800-604-0858 for more information.
- VNA set-up, calibration approach and verification
- S-parameter quality workflow
- Differential mode analysis
- Building S24P models from 4-port S4P measurements
- Measurement considerations for EDA simulation to measurement correspondence