Isola Astra® MT77 High-Frequency Laminate & Custom multilayer PCB Solutions – very low- loss Dk product for millimeter wave frequencies

Product Description

Astra® MT77 High-Frequency Laminate & Custom PCB Solutions – Full Overview

 

Q: What is Astra® MT77, and what kind of PCB can we deliver based on it?

A: Astra® MT77 is Isola’s ultra-low loss, high-thermal-resistance laminate and prepreg system, specifically engineered for millimeter-wave (mmWave) and RF/microwave applications. Key parameters: Dk = 3.00, Df as low as 0.0017, Tg = 200°C, and Td = 360°C.

 

 

Based on this material, we offer fully MT77-based, 6-layer, mixed-pressure PCBs with advanced HDI features including blind vias (L1–L2, L5–L6), G12 resin plugging, and electroplated via filling. The reference product in this document is specified as: 6-layer copper, 0.994mm finished thickness, inner 0.5oz / outer 1oz copper, immersion silver finish, green solder mask with white legend, 131mm × 107mm panel.

 

 

Key Takeaways

	Key Highlight	Description
①	Material Grade	Astra® MT77 – purpose-built for mmWave and beyond, outperforming conventional FR-4 and many PTFE-based materials.
②	Electrical Performance	Dk = 3.00 (stable from 2–10GHz), Df = 0.0017 (@10GHz) – delivering excellent signal integrity at high frequencies.
③	Thermal Reliability	Tg = 200°C, Td = 360°C – fully compatible with lead-free soldering and demanding operating environments.
④	Process Compatibility	Supports standard FR-4 fabrication processes – no special handling required, reducing cost and lead time.
⑤	Manufacturing Capability	Supports blind vias (L1–L2, L5–L6), G12 resin plugging + electroplated filling, and other advanced HDI processes.
⑥	Industry Compliance	Meets IPC-4103 /17, UL 94 V-0, and UL RTI 130°C (File No. E41625).

 

 

1. Material Overview – Why Astra® MT77?

Astra® MT77 is a breakthrough, very-low-loss dielectric product tailored for commercial RF, microwave, and millimeter-wave frequencies. Its unique formulation bridges the gap between high-performance PTFE laminates and conventional epoxy-based materials – delivering superior electricals while remaining fully compatible with standard PCB manufacturing lines.

 

 

Key material properties (based on official datasheet):

Property	Typical Value	Unit	Test Method (IPC-TM-650)
Glass Transition Temp. (Tg) by DSC	200	°C	2.4.25C
Decomposition Temp. (Td) @5% wt loss	360	°C	2.4.24.6
T260 / T288 Delamination (TMA)	>60 / –	Minutes	2.4.24.1
Z-CTE (Pre-Tg / Post-Tg)	50–70 / 250–350	ppm/°C	2.4.24C
X/Y-CTE (Pre-Tg)	12	ppm/°C	2.4.24C
Thermal Conductivity	0.45	W/m·K	ASTM E1952
Moisture Absorption	0.1	%	2.6.2.1A
Flammability Rating	V-0	–	UL 94
RTI (Relative Thermal Index)	130	°C	UL 796

 

 

2. Electrical Performance – Critical for High-Frequency Design

Parameter	Condition	Value	Test Method
Dk (Permittivity)	@ 2 GHz / @ 10 GHz	3	2.5.5.5
Df (Loss Tangent)	@ 2 GHz / @ 10 GHz	0.0017	Bereskin Stripline
Volume Resistivity	C-96/35/90	1.33 × 10⁷	MΩ-cm	2.5.17.1
Surface Resistivity	C-96/35/90	1.33 × 10⁵	MΩ	2.5.17.1
Dielectric Breakdown	–	45.4	kV	2.5.6B
Arc Resistance	–	139	Seconds	2.5.1B
Electric Strength (Laminate & prepreg)	–	45 (1133)	kV/mm (V/mil)	2.5.6.2A
CTI (Comparative Tracking Index)	Class 3	175–249	Volts	UL 746A / ASTM D3638

 

 

Why this matters:

 

Ultra-low Df minimizes insertion loss – critical for 5G, automotive radar (77GHz), and satellite links.

 

Stable Dk across frequency ensures consistent impedance control, reducing return loss and signal distortion.

 

 

3. Mechanical & Thermal Reliability

Property	Value (Length / Cross direction)	Unit	Test Method
Peel Strength (1 oz EDC foil)	1.0 (5.7)	N/mm (lb/in)	2.4.8.3
Flexural Strength	338 (49.0) / 269 (39.0)	MPa (kpsi)	2.4.4B
Tensile Strength	214 (31.0) / 165 (24.0)	MPa (kpsi)	ASTM D3039
Poisson’s Ratio	0.183 / 0.182	–	ASTM D3039

 

 

 

Design implications:

 

High Tg and Td allow reliable operation in high-power RF environments.

 

CTE matching with copper reduces plated-through-hole (PTH) stress during thermal cycling.

 

 

4. Custom PCB Reference – 0.994mm 6-Layer Board

This section describes the actual product we have manufactured, demonstrating our technical capability with this material.

 

 

Basic Specifications

Item	Specification
Layer Count	6-layer copper
Material Stack	3 × 0.127mm MT77 cores + MT77 prepreg (fully MT77-based)
Finished Board Thickness	0.994mm
Inner Layer Copper	0.5 oz
Outer Layer Copper	1.0 oz
Surface Finish	Immersion Silver
Solder Mask / Legend	Green solder mask / White silkscreen
Panel Size	131mm × 107mm (1 piece)

 

Stack - up

 

Advanced Process Features

Property	Value (Length / Cross direction)	Unit
Peel Strength (1 oz EDC foil)	1.0 (5.7)	N/mm (lb/in)
Flexural Strength	338 (49.0) / 269 (39.0)	MPa (kpsi)
Tensile Strength	214 (31.0) / 165 (24.0)	MPa (kpsi)

 

 

Comparison Table – MT77 vs. Alternative High-Frequency Materials

Parameter	Astra® MT77	Standard FR-4 (High-Tg)	Typical PTFE-Based Laminate
Dk @ 10GHz	3	~4.2–4.5	~2.9–3.2
Df @ 10GHz	0.0017	~0.015–0.020	~0.0015–0.0025
Tg	200°C	~170–180°C	~180–240°C (varies)
Td	360°C	~340°C	~400°C+
Moisture Absorption	0.10%	~0.3–0.5%	<0.1%
FR-4 Process Compatibility	Yes	Yes	Limited (requires special handling)
Cost Level	Mid-High	Low	High
Best Application	mmWave, 5G, Radar	General digital, low-speed RF	High-end microwave, aerospace

 

Conclusion: MT77 delivers near-PTFE electrical performance with FR-4 manufacturability – a balanced choice for commercial mmWave products.

 

 

Application Areas

 

Automotive Radar – 77GHz adaptive cruise control, blind-spot detection, collision warning

 

5G Infrastructure – mmWave base stations, small cells, beamforming antennas

 

Satellite Communications – Ku/Ka-band terminals, phased-array antennas

 

Aerospace & Defense – radar systems, electronic warfare, high-reliability RF modules

 

High-Speed Digital – 400G/800G optical transceivers, test & measurement equipment

 

Our custom PCB – with blind vias, resin plugging, and electroplated filling – is particularly suited for high-density RF front-end modules and phased-array antenna panels where signal integrity and thermal management are critical.

 

 

Q1: Is Astra® MT77 compatible with standard FR-4 processing?

A: Yes. Unlike PTFE-based materials, MT77 can be processed using conventional FR-4 equipment and parameters, significantly reducing manufacturing cost and lead time.

 

 

Q2: What copper foil types are supported?
A: The datasheet references VLP/HVLP (low-profile / very-low-profile) foils, which are optimized for low insertion loss at high frequencies.

 

 

Q3: Can you support impedance-controlled designs with this material?
A: Absolutely. The stable Dk value of 3.00 allows precise impedance modeling. We can tailor trace widths and stack-up to meet your specific impedance requirements.

 

 

Q4: What is the maximum layer count you can build with MT77?
A: We support up to 12+ layers with MT77, depending on the stack-up and via structure.

 

 

Q5: Is immersion silver the only finish available?
A: No. We also offer ENIG, ENEPIG, immersion tin, and OSP. Immersion silver is recommended for RF applications due to its low contact resistance and lack of a nickel barrier layer.

 

 

Q6: What is the lead time for such a custom PCB?
A: Typical lead time for MT77-based multilayer boards with HDI features is 8–10 working days for prototypes, with shorter lead times available upon request.

 

 

Q7: Do you provide design support or stack-up recommendations?
A: Yes. Our engineering team can assist with stack-up design, impedance calculation, and DFM (Design for Manufacturability) reviews.

 

 

Contact Us
For technical inquiries, pricing, or sample requests, please reach out to our team. We are ready to support your project from prototype to volume production with full material traceability and quality assurance.