Frequency Filter

Frequency Filter (Step 3.7)

Multi-stage frequency-aware filtering that addresses the blind spot where paper titles/abstracts often don't mention specific frequencies.

4 Stages

1. Embedding type rank — Already done by embedding searcher (device type match)
2. Band-label matching — Translates user freq to general terms (microwave, mmW, THz, IR, IEEE bands) and checks title/abstract
3. Frequency extraction — Regex extracts actual GHz/THz/MHz values from text, checks overlap with target range (±20% tolerance)
4. Broadband sub-range — For broadband targets, accepts narrowband papers within the target range and suggests array/supercell combination

Scoring

• Exact frequency overlap: 0.5 + 0.5 × overlap_fraction (up to 1.0)
• Band label match, no freq data: 0.4
• Band label match but wrong freq: 0.2
• No match, no data: 0.1
• Wrong frequency regime: 0.05