High frequency PCB

Uses low-loss materials (such as Rogers 4350B), with line width tolerance ±0.01mm, signal layer spacing control accuracy ±5%, and impedance control accuracy ±5Ω.

5G base stations (24.25-52.6GHz), satellite communications (Ka band 26.5-40GHz), millimeter-wave radar (77GHz), high-speed data centers (100Gbps+).

Quantitatively evaluated by parameters such as insertion loss (＜-3dB@10GHz), return loss (＞-20dB@10GHz), and crosstalk (＜-30dB).

Related to material molecular structure, temperature (Df increases by 3%-5% for every 10℃ rise), and frequency (Df increases with the square of frequency).

Rogers 4350B (Dk=3.48, Df=0.0037), Taconic TLY-5 (Dk=2.2, Df=0.0009), Isola 370HR (Dk=3.6, Df=0.004).

Low Dk materials reduce transmission delay (e.g., Dk=2.2 materials have 25% faster delay than FR-4), and low Df reduces signal attenuation (loss is 70% lower than FR-4 when Df=0.001).

Water absorption >0.5% causes Dk fluctuations exceeding 5%. It is recommended to use materials with water absorption <0.1% (such as Rogers 4350B with 0.04% water absorption).

Prioritize materials with Dk＜2.5 and Df＜0.001 (such as Arlon AD255, Dk=2.5, Df=0.0008) to meet 24-100GHz applications.

Adding aluminum oxide ceramics can increase the material Tg to 280℃+ and reduce the coefficient of thermal expansion (CTE) to 2-3ppm/℃, improving high-temperature stability.

In conventional processes, line width/spacing ≥50μm; advanced processes can reach 30μm, requiring impedance control matching.

Use symmetrical stacking, with a spacing ≤0.1mm between power and ground layers and ≤0.05mm between signal and reference layers to reduce electromagnetic interference.

Ordinary vias cause -3dB loss at 10GHz. Using back-drilling (removing excess stub length) can reduce loss by over 60%.

Avoid right-angle routing (reflection increases by 15%), prioritize 45° corners; control signal loop area < (signal wavelength)²/100.

Use CO₂ laser drilling (aperture accuracy ±5μm) to avoid delamination from mechanical drilling, with hole wall roughness Ra≤1.2μm.

Use electroless copper plating + electroplating copper, control copper layer roughness Rz≤2μm to reduce surface loss (loss increases by 10% for every 1μm increase in roughness).

Electroless nickel immersion gold (ENIG) with a thickness of 1-3μm and contact resistance <50mΩ; OSP with a thickness of 0.2-0.5μm is suitable for high-speed signals but has poor storage resistance.

Lamination temperature should be controlled at material Tg+30℃ (e.g., Rogers 4350B lamination temperature 210-230℃), with pressure 5-8MPa to avoid delamination.

Use TDR (time-domain reflectometer) to detect impedance continuity, X-ray to detect via position deviation (allowable ±0.05mm), and AOI to detect line width tolerance.

Use low Df materials, optimize copper foil roughness (RTF copper foil has 30% lower loss than RA copper foil), and shorten trace length.

Check impedance discontinuities (such as vias, connectors), ensure impedance deviation <±5Ω, and optimize trace transition areas.

Excessive parallel trace length causes crosstalk. Increasing line spacing to the 3W principle (W is line width) and adding ground isolation can reduce crosstalk by 20dB.

Terminate with matching resistors (resistance = transmission line impedance) and use gradual line width transitions to reduce the reflection coefficient below 0.1.

Shield with a complete ground plane (gap <λ/20, λ is wavelength) and use a shield can reduce radiation intensity by 40dB.

Conduction through copper foil (thermal conductivity 398W/mK) accounts for 70%, material conduction 20%, and convection/radiation 10%.

Increase heat via density (≥200/cm²), use thick copper foil (≥3oz), and combine with heat sinks to reduce thermal resistance by 40%.

Aluminum substrate (170W/mK) > copper substrate (398W/mK) > ordinary FR-4 (0.35W/mK).

For every 10℃ rise, Dk increases by 0.5%-1%, and Df increases by 3%-5%. The recommended operating temperature is <85℃.

Via diameter 0.3-0.5mm, spacing ≤1mm to ensure effective heat conduction paths and reduce thermal resistance by 30%.

S-parameter testing (S11, S21, etc.), impedance testing, dielectric loss testing, temperature cycling testing (-40℃~125℃, 500 cycles).

S11 (return loss), S21 (insertion loss). The test frequency range covers the operating band with an accuracy of ±0.5dB.

Conduct damp heat testing (85℃/85% RH, 1000h) and salt spray testing (5% NaCl, 24h) to verify material weather resistance.

Measures the reflection waveform by emitting a step signal to locate impedance discontinuities, with a resolution of up to 0.1mm.

Use anechoic chambers to test radiated emissions (≤-40dBμV/m@1GHz) and shield effectiveness testing (>60dB).

Use nitrogen reflow soldering (oxygen content <50ppm) with a peak temperature of 230-250℃ to avoid material delamination.

Select high-frequency connectors such as SMA, 2.92mm, 1.85mm, etc., with operating frequencies covering the required band and insertion loss <0.5dB.

Ensure impedance matching between connectors and PCBs, and clean the terminals after soldering to reduce loss by 15%.

Need to meet the 24-52GHz band requirements and solve heat dissipation (power density >10W/cm²) and miniaturization issues.

Pass AEC-Q200 certification, with an operating temperature of -40℃~125

IPC-4101 (base material specification), IPC-6012 (rigid board acceptance standard), IEEE 802.3 (high-speed signal standard).

Complies with MIL-PRF-55110 (microwave circuits), operating temperature -55℃~125℃, passed salt spray and mold tests.

Meets AEC-Q200 (passive component certification) and ISO 26262 (functional safety) requirements.

Meets 3GPP TR 38.810 (base station equipment), insertion loss < -2dB@28GHz, return loss > -15dB.

Follows NASA-STD-8739.3 (electronic materials), passed 1000-hour damp heat test, Dk change < 2%.

Ultra-low loss materials (Df < 0.0005), low-temperature processable materials (lamination temperature < 150℃).

CTE reduced to 1ppm/℃, thermal conductivity increased to 100W/mK, while maintaining low Dk (2.8).

Flexible materials have slightly higher Dk (3.0-3.5) and 20%-30% higher Df, but enable 3D routing.

Eco-friendly materials (such as linen fiber-based) with Dk=3.2 and Df=0.004, suitable for consumer electronics.

Al₂O₃ ceramic substrate with Dk=9.8 and thermal conductivity 24W/mK, suitable for power device integration.

Altium Designer, Cadence Allegro, ANSYS HFSS (electromagnetic simulation), Keysight ADS (circuit simulation).

Build a 3D model, set material parameters and boundary conditions, simulate S-parameters and field distribution with an error < 5%.

Performs circuit-level simulation, optimizes matching networks, predicts insertion loss and return loss, and supports multi-port S-parameter analysis.

Error within ±3Ω, requiring calibration with actual process parameters (such as copper foil roughness, dielectric thickness).

Adjust trace layout based on field distribution, optimize impedance matching through parameter scanning, and iteratively design to reduce losses.

Laser drilling machine (accuracy ±5μm), vacuum laminator, high-precision etching machine (line width tolerance ±0.01mm).

CO₂ laser suitable for thick boards (>1mm) with large apertures (≥0.3mm); UV laser suitable for thin boards (<0.5mm) with small apertures (0.1-0.2mm).

Vacuum degree < 100Pa, temperature uniformity ±2℃, pressure control accuracy ±0.5MPa.

Etch factor ≥3:1, ensuring side etch amount < 0.02mm to meet fine-pitch routing requirements.

Can detect line width/spacing deviation (±0.005mm), shorts/open circuits, minimum defect size 0.01mm.

Complies with RoHS 2.0 (restricts 6 hazardous substances such as lead and mercury), halogen content < 900ppm.

Use lead-free soldering, heavy metal content < 0.1mg/L after wastewater treatment, and recycle scraps (recovery rate > 95%).

Recover copper through physical crushing + chemical dissolution (recovery rate > 98%), and harmlessly treat resin waste.

Polylactic acid-based materials with Dk=3.3 and Df=0.005, degradation rate > 80% within 180 days after use.

Environmental processes increase costs by 10%-15%, but compliance avoids penalty risks.

AI algorithms optimize routing topology, reducing manual design time by 50% and signal loss by 15%.

Enables complex 3D structures with interlayer alignment accuracy ±0.05mm, but material loss is currently high (Df=0.01).

Requires ultra-low loss materials (Df < 0.0001) and signal transmission delay < 1ns/m.

Requires materials with Dk < 2.0 and Df < 0.0005, which existing technologies struggle to meet for 100-300GHz requirements.

Adopts 2.5D/3D packaging technology to shorten signal paths and reduce system loss by 30%.

Avoid high-temperature and high-humidity environments (temperature < 60℃, humidity < 60% RH), and regularly clean surface dust (electrostatic dust removal).

Use back-drilling to remove excess via stubs, with stub length ≤1/8λ; use through-hole reflow soldering to reduce parasitic capacitance.

Prioritize low Dk (<3) and low Df (<0.005) materials, such as Rogers 4350B and Isola 370HR.

Test S-parameters with a network analyzer, requiring S11 ≤ -15dB and characteristic impedance error ±5Ω; use TDR to observe reflection coefficient < 0.1.

Dielectric layer thickness 0.05-0.2mm, copper foil roughness Ra≤0.5μm; adjacent layer traces orthogonal, power/ground layer spacing < λ/20.

Use metal shielding cans (shielding effectiveness ≥80dB) with gap width < λ/20; add ground via arrays at PCB edges.

Line spacing ≥3×line width, length error <5mil; embedded microstrip lines require distance to reference plane matching impedance calculations.

ENIG provides smooth surface and low loss; OSP's thin thickness suits high-frequency applications, avoiding magnetic loss from nickel layers.

Use HFSS/CST for full-wave electromagnetic simulation to verify SI/PI; perform S-parameter sweep analysis at ≥10 frequency points.

Select materials with CTE ≤15ppm/℃, increase heat via density (≥20/cm²), and use metal-based copper-clad boards.

Use PTFE-based low Df materials; optimize dielectric layer thickness to meet λ/4 resonance conditions and reduce energy loss.

Line width tolerance ±0.02mm causes impedance 波动 ±3Ω; dielectric thickness tolerance ±0.01mm causes Dk deviation ±0.1, requiring strict control.

Place MLCC combinations (10nF/100nF/1μF) at the power inlet; partition the power layer with ≥50mil spacing between voltage domains.

Fixture contact impedance < 0.1Ω, insertion loss < 0.5dB; use SMA/K-type connectors covering the signal frequency band.