calc.engineer

microstrip

microstrip

Calculate PCB microstrip trace width for a target characteristic impedance using the Hammerstad-Jensen closed-form equations. Given target impedance (Z0), substrate dielectric constant (er), substrate height, and copper weight, returns the required trace width and effective dielectric constant. Optionally computes effective wavelength at a given frequency. Essential for RF PCB layout to achieve controlled impedance traces (e.g. 50 ohm for SMA connectors). References IPC-2141.

Input Schema

TableJSON Schema

Name	Required	Description
`er`	No	Substrate relative dielectric constant (default 4.6 for FR-4)
`z0_ohm`	No	Target characteristic impedance in ohms (default 50)
`freq_mhz`	No	Optional frequency in MHz for effective wavelength calculation
`copper_oz`	No	Copper weight in oz/ft2 (1 oz = 0.035 mm thickness)
`height_mm`	Yes	Substrate height (dielectric thickness) in millimetres

Output Schema

TableJSON Schema

Name	Required	Description
`er_eff`	Yes	Effective dielectric constant of the microstrip
`width_mm`	Yes	Required trace width in millimetres
`wavelength_eff_mm`	Yes	Effective wavelength in millimetres at the given frequency (null if freq not provided)

TDQS

A4/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Discloses use of closed-form equations and optional wavelength calculation. No annotations are provided, so the description bears full burden. However, it does not discuss limitations like frequency range, accuracy, or edge effects, leaving some behavioral ambiguity.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, well-structured and front-loaded. Every sentence adds value without redundancy. Efficient and clear.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Covers inputs, equations, outputs, and references IPC-2141 with an example. Complex tool with output schema present. Could mention applicability domain (e.g., frequency range) but overall complete enough for most use cases.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the schema already documents parameters. The description adds a little context (e.g., 'default 4.6 for FR-4') but does not significantly enhance understanding beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool calculates PCB microstrip trace width for target impedance using Hammerstad-Jensen equations. It specifies input parameters and outputs, and distinguishes from sibling tools by focusing on microstrip geometry.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Provides context that it's essential for RF PCB layouts to achieve controlled impedance, with an example (50 ohm for SMA). Does not explicitly exclude cases like stripline or give alternatives, but the context is clear enough.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

All calc.engineer tools Inspect

Try in Browser

RayrunBuild, deploy, and operate MCP servers without becoming an infrastructure team.ray.runAd

Glama MCP Gateway

Add one secure layer between your agents and this server.

TDQS

A3.9/5.0

Disambiguation4/5

Despite 89 tools, each has a clearly distinct purpose with detailed descriptions that often reference related tools. Overlap exists (e.g., multiple LoRa/RF tools), but the descriptions are sufficient to distinguish them. Some confusion possible among similar-sounding tools like attenuator_pi and attenuator_tee, but the descriptions explicitly compare them.

Naming Consistency4/5

Consistent underscore-separated lowercase naming. Most tools follow a verb_noun pattern (e.g., capacitor_charge, wire_gauge) or noun_noun (power_cost). Minor inconsistencies such as 'bmi_calculator' vs 'solar_sizing' but overall predictable.

Tool Count2/5

89 tools is far too many for a single MCP server. This scope is more appropriate for multiple specialized servers. The sheer number will slow agent selection and increase cognitive load, reducing coherence.

Completeness3/5

Covers many domains (RF, solar, PCB, networking, math, etc.) but lacks depth in some areas (e.g., no three-phase power, no airflow calculations). Some domains have comprehensive coverage (LoRa/Meshtastic), but others feel incomplete for the tool count.

Resources

Need Help?