mmWave Frequency Bands and Applications
| Frequency | Band | Application |
|---|---|---|
| 24 GHz | K-band | Automotive radar (SRR), ISM |
| 28 GHz | Ka-band | 5G NR n257 mmWave |
| 39 GHz | Ka-band | 5G NR n260 mmWave |
| 60 GHz | V-band | WiGig (802.11ad), point-to-point |
| 77 GHz | W-band | Automotive LRR radar (ACC) |
mmWave S-Parameter File Considerations
At 28–77 GHz, S-parameter files require: - Fine frequency resolution: ≤100 MHz per point for accurate group delay - Wide frequency range: typically 20–100 GHz for out-of-band characterization - Large file size: 1000 frequency points = 9000 data columns for .s2p RF View handles these files without issues on modern Android devices (4GB RAM+) For very large files (10,000+ points): allow a few seconds to load
28 GHz Filter Analysis (5G n257)
Load 28 GHz BPF .s2p (n257: 26.5–29.5 GHz):
BW Marker → reads: f₀, 3dB BW, IL
Typical 5G mmWave filter specs:
IL: <2 dB across 26.5–29.5 GHz
BW: 3 GHz
Shape factor: <1.4 (waveguide cavity or LTCC)
Group delay ripple: <50 ps across any 400 MHz block
Switch to Group Delay view → verify flatness across sub-bands
77 GHz Automotive Radar Antenna Analysis
Load 77 GHz patch antenna array .s1p (or .s2p for active integrated): Frequency range: 76–81 GHz (automotive radar band) S11 view → verify VSWR <2:1 across 76–81 GHz (5 GHz bandwidth!) Smith chart → check impedance locus across 5 GHz span If poorly matched: design microstrip matching on RT/Duroid 5880 RF View Microstrip Calculator → εr=2.20 (RT/Duroid 5880) → Compute W and λ/4 at 77 GHz: λ/4 ≈ 0.97 mm (only 1mm on substrate!)
mmWave PCB Requirements
- Substrate: RT/Duroid 5880 (εr=2.20, tan δ=0.0009) essential above 20 GHz
- Trace width for 50Ω at 77 GHz: 0.38 mm on 5 mil (0.127mm) Duroid 5880
- Via diameter: use minimum 0.1–0.2 mm for signal vias above 40 GHz
- Connector: 2.92mm (40 GHz rated) or 1.85mm V-connector for 67 GHz
RF View mmWave: Load any .s2p file regardless of frequency range. RF View handles 100 GHz S-parameter files. Microstrip Calculator supports all substrate types for mmWave trace design. Free on Android.