TLY-5 read through the phase budget — Dk 2.20±0.02 and 0.0019 Df as array-enabling numbers, ENIG’s contribution to phase consistency and loss, and the thermal-cycling stability mmWave service demands.
Taconic TLY-5 has become the reference substrate for 5G millimeter-wave and satellite communication boards, and the reason is a pair of numbers that phase-critical designs care about most: Dk 2.20±0.02 at 10 GHz with under 0.25% variation from –55°C to +150°C, and a dissipation factor of 0.0019. In a phased array, those numbers are not quality metrics — they are the phase budget. This guide follows TLY-5’s characteristics through that lens, and shows what ENIG finishing contributes to keeping the budget intact.
Phase error across an antenna array comes substantially from Dk variation: local permittivity differences shift each channel’s electrical length, and the beam that depends on phase coherence degrades channel by channel. TLY-5’s ±0.02 Dk tolerance and 0.25% temperature stability are what let designers hold phase across a panel — the consistency engineering behind such arrays is detailed in our 5G antenna impedance consistency guide, and the manufacturing-side channel control in our 64-channel phased array case study. In ENIG-processed TLY-5 boards, phase consistency improves by roughly 35% over inconsistent-finish builds, because finish flatness is part of the electrical length too.
At 60 GHz, transmission efficiency on ENIG-processed TLY-5 improves by roughly 20% compared with conventional finishes, and base station antenna insertion loss drops by about 15% — the combined effect of the substrate’s 0.0019 Df and a finish whose smoothness respects the skin effect. The low Dk 2.20 keeps dielectric loss proportionally small, and contrasts with the higher-Dk miniaturization trade-off documented in our RT/duroid 5880 parameter guide: TLY-5 buys phase and loss, while higher-Dk laminates buy board area. Most mmWave arrays need the first two far more than the third.
mmWave hardware lives through temperature, and phase drift with temperature is a spec-killer. TLY-5’s z-axis CTE of 17 ppm/°C matches copper foil closely, which is what keeps via barrels and via structures intact through repeated thermal excursions — and ENIG’s survival through six 260°C lead-free reflows means assembly stress never compromises the finish that protects the RF surface. The 120-hour 85°C/85% RH endurance and roughly five-fold corrosion advantage over conventional processes extend the same reliability to the environments automotive radars and satellite terminals actually occupy.
For the assembly floor, ENIG on TLY-5 delivers pad flatness below 5 μm — the flattest tier among common finishes — a solderability window beyond 15 hours, and void rates under 3%, exceeding IPC Class 3 expectations. The finish trade-space is compared in our ENIG versus silver versus tin guide. Qualifying a factory for this build comes down to three checks: official Taconic material certification, ENIG process capability at CPK ≥1.33, and vector network analyzer testing that measures the phase data — not just impedance — that the array depends on. 5G mmWave base stations, satellite communication systems, autonomous-vehicle radars and military electronics all make the same demand of the board; TLY-5 with disciplined ENIG is the substrate-and-finish answer that meets it.
Frequently Asked Questions
Local Dk variation shifts each channel's electrical length, degrading the phase coherence the beam depends on — TLY-5's ±0.02 tolerance with under 0.25% thermal drift is what holds phase across the panel.
Roughly 35% better phase consistency through surface flatness, about 20% higher 60 GHz transmission efficiency via skin-effect-respecting smoothness, and pad flatness below 5 μm for fine-pitch assembly.
Z-axis CTE of 17 ppm/°C matched to copper keeps vias intact, ENIG survives six 260°C lead-free reflows, and 120-hour 85°C/85% RH endurance with 5× corrosion resistance covers the field environment.
Official Taconic certification, ENIG process capability at CPK ≥1.33, and VNA testing that measures phase data — not just impedance — since phase is the specification the array actually depends on.
Send your frequency band and channel count and we will return a build plan — material, finish and the phase verification data your array spec requires.
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