Unit 5 — Calibration and Verification

TM-GEAR-009 — Open Handout TM Chapters: Chapter 6, Chapter 7 ELOs: Calibrate the RF HYBRID COUPLERS — QUADRATURE, WILKINSON, AND RAT-RACE; verify performance against acceptance criteria; complete calibration log Estimated time: 45 minutes (actual lab work required)

Step 1: Read the TM

Open TM-GEAR-009. Read Chapter 6 — Calibration and Chapter 7 — Verification and Acceptance completely.

Then come back here.

Chapter 6 — Calibration Content

1. Branch-line hybrid: with NanoVNA, measure S11 at Port 1 (must be <−20 dB return loss at f0) and S21 to ports 2 and 3 (−3 ± 0.5 dB each). Measure S31 vs. S21 phase (must be −90 ± 5°). S41 must be <−30 dB (isolation).
2. Wilkinson: S11 <−20 dB; S21 = S31 = −3 ± 0.5 dB; S23 (isolation) <−20 dB at center frequency.

Chapter 7 — Verification Content

1. Amplitude balance: |S21| − |S31| <0.5 dB.
2. Phase accuracy: Δφ within ±5° of design value (90° or 0°) at center frequency.
3. Return loss (input match): <−20 dB at center frequency.
4. Isolation: <−20 dB between output ports.
5. Power handling (Wilkinson): verify 100Ω isolation resistor rating. At 100W input, the resistor dissipates up to 50W if ports 2 and 3 are mismatched — use 5W resistor minimum.
6. Log: date, design type, center frequency, S21/S31 balance, phase error, return loss, isolation, operator.

Calibration vs. Verification — Distinction

Calibration (Chapter 6): active adjustments to bring the component within specification. You are permitted to adjust, tweak, and repeat until the criterion is met.

Verification (Chapter 7): independent confirmation that the calibration succeeded. No adjustments are permitted during verification. If a verification check fails, you return to Chapter 6, not to Chapter 7.

Acceptance Criterion

A criterion found in Chapter 6: 20 dB. Confirm the exact criterion in the TM.

Write the exact criterion from the TM here before you start the lab:

Lab Checklist

Work through each item in sequence. Do not skip steps.

• [ ] All required equipment gathered and ready
• [ ] Equipment warmed up per TM requirements
• [ ] All Chapter 4 setup steps verified complete
• [ ] Chapter 6 calibration performed (all steps)
• [ ] Calibration criterion met (recorded below)
• [ ] Chapter 7 verification performed (all steps, no adjustments)
• [ ] All verification criteria passed
• [ ] Calibration log entry completed

Calibration Log Entry

• [ ] Date
• [ ] Equipment used
• [ ] Measurements taken
• [ ] Results vs. criteria
• [ ] Operator name

Record your results:

Self-Check Questions

SC5-1. What is the acceptance criterion for this calibration (from Chapter 7)?

SC5-2. During verification, one reading fails. What is the correct action per the TM?

SC5-3. List the items required in a calibration log entry per Chapter 7.

SC5-4. What is the difference between calibration and verification in this context?

SC5-5. If the component passes all Chapter 7 checks, what does that tell you about its current state?

Answer Key

SC5-1. See Chapter 7. The criterion is stated as a specific value with units.

SC5-2. Stop verification. Return to Chapter 6 and re-calibrate. Diagnose the cause before re-adjusting.

SC5-3. See Chapter 7, last numbered step. The log items are listed there.

SC5-4. Calibration allows adjustments; verification does not. Verification is independent confirmation.

SC5-5. It tells you the component is performing within its specified parameters at this time. It does not tell you how long it will remain in calibration — periodic re-verification is required.

Checkpoint

You are ready for the final assessment when you can: - [ ] State the acceptance criterion from memory - [ ] State the difference between calibration and verification - [ ] State the required log items from memory

→ Proceed to Final Assessment