Top Strategies for Minimizing Signal Loss in High-Frequency PCB Designs

Tony Zh Yi

·July 9, 2025

·9 min read

Top Strategies for Minimizing Signal Loss in High-Frequency PCB Designs — Image Source: pexels

Minimizing signal loss in high-frequency PCBs needs careful material choice, exact design, and advanced making. Signal integrity problems, like signal attenuation and crosstalk, can cause circuit boards to not work well. More people want high-frequency uses, so fixing signal loss and signal attenuation is now very important. LT CIRCUIT gives new ways to help keep signal integrity and lower signal attenuation.

Key Takeaways

Pick low-loss materials with a low dielectric constant and dissipation factor. This helps lower signal loss and makes timing better in high-frequency PCBs.
Make PCBs with controlled impedance, good stackup, and careful trace layout. This stops signal reflections, crosstalk, and electromagnetic interference.
Use advanced ways to make PCBs and test them well. This keeps signals strong and meets tough industry rules for high-frequency PCB performance.

Material Selection for High-Frequency PCBs

Dielectric Properties and Signal Loss

Picking the right material is very important for high-frequency PCB making. The dielectric constant (Dk) and dissipation factor (Df) of materials affect signal loss and signal attenuation. If engineers use materials with a high dielectric constant, signals move slower. This can cause impedance mismatches. These mismatches make reflections and more signal loss, especially in high-frequency PCBs. A high dissipation factor means more signal energy turns into heat. This causes even more signal attenuation.

When the frequency is above 1 GHz, normal solder mask materials with Dk between 3.5 and 4.5 and Df between 0.02 and 0.03 can cause a lot of signal problems. But if you use solder mask materials with low Dk (2.5 to 3.0) and low Df (less than 0.01), you can lower signal loss and make timing better. For example, in a 10 GHz design, using a low Dk solder mask can make timing better by up to 10%. In a 28 GHz 5G base station, changing from a normal solder mask to a low loss solder mask made signal loss go down from 0.8 dB per inch to 0.3 dB per inch. This helps meet the tough needs of high-frequency and radio-frequency uses.

Material Property Change	Change Magnitude	Effect on Insertion Loss	Frequency	Notes
Dielectric Constant (Dk) Reduction	20% decrease (4.0 to 3.2)	13.2% reduction in insertion loss (with same thickness and gap, increased line width)	N/A	Reduction in thickness alone offsets gain; wider line width needed to realize insertion loss benefit
Dissipation Factor (Df) Reduction	50% decrease (0.005 to 0.0025)	50% reduction in dielectric loss, but only 15.2% reduction in insertion loss at 20 GHz	20 GHz	Dielectric loss is a smaller component of total insertion loss, limiting overall insertion loss improvement

This table shows that using low Dk and low Df materials can really help lower insertion loss and signal attenuation in high-frequency PCB making. But how much it helps depends on the PCB design and how much dielectric loss adds to the total insertion loss.

Advanced Materials for Minimizing Signal Loss

Top companies in high-frequency PCB making use special materials to lower signal loss and signal attenuation. Some low loss solder mask materials, like epoxy-based and polyimide-based types, have dielectric constants between 2.5 and 3.0 and loss tangents below 0.005. These solder mask materials are great for high-frequency PCBs, like those in 5G, car radar, and satellites. Using a low Dk solder mask (about 2.8) instead of a higher Dk (4.0) can make timing better by up to 10% at 10 GHz. Low loss solder mask materials with Df below 0.01 can cut signal attenuation by up to 20% in fast PCB designs at 25 Gbps.

Some advanced rf pcb materials, like Rogers 4000 series and Panasonic Megtron, give even more benefits. These materials have low dielectric loss, controlled dielectric constant, and low z-axis expansion. Rogers materials are used a lot for microwave and radio-frequency uses. Megtron materials work well for high-frequency signals too. Both help keep signals strong, lower signal loss, and make high-frequency PCB making better.

Smooth copper foils, like rolled annealed copper, make high-frequency PCBs work even better. These copper foils are very smooth, which lowers insertion loss and signal attenuation. Low surface roughness makes conductivity and sticking better, which is important for keeping signals strong at high frequencies. Copper’s low dielectric constant and low dielectric loss stop signal loss during transmission. The special in-plane crystal structure of rolled annealed copper lets circuits bend and work in high-frequency uses.

Tip: In microstrip and coplanar waveguide transmission lines, solder mask materials touch the electromagnetic field. Using less solder mask or picking low loss solder mask materials keeps signals strong and lowers insertion loss.

LT CIRCUIT’s Expertise in High-Frequency PCB Manufacturing

LT CIRCUIT is a leader in high-frequency PCB making because it uses the best materials and new pcb manufacturing technology. The company makes many kinds of high-frequency PCBs, like HDI PCB boards, multilayer PCBs, and advanced HDI any layer PCBs. These products use top rf pcb materials, low loss solder mask materials, and smooth copper foils to keep signal loss and signal attenuation very low.

LT CIRCUIT’s products help with high-speed PCB and high-frequency uses by giving many lamination choices and different surface finishes. The company uses low loss solder mask materials and special solder mask properties to lower insertion loss and keep signals strong. LT CIRCUIT always makes sure every high-frequency PCB meets tough industry rules for signal loss, insertion, and efficiency.

Customers get a lot from LT CIRCUIT’s skill in picking materials, solder mask materials, and copper technology. The company’s focus on low-loss materials and special solder mask properties helps give strong high-frequency signals and great performance in radio-frequency uses. LT CIRCUIT’s promise to be new and exact makes it a trusted partner for high-frequency PCB making.

Design Strategies to Minimize Signal Loss

PCB Stackup and Impedance Control

Engineers plan the PCB stackup carefully to lower signal loss. A good stackup gives steady reference planes and keeps impedance even. This helps stop electromagnetic interference and lowers insertion loss.

Best ways to control stackup and impedance are:

Change circuit width and space to get the right impedance.
Build the PCB layers to cut down EMI and give steady reference planes.
Pick low-loss dielectric materials like FR4 or polyimide to stop signal problems.
Make transmission lines short to help signals move better and lose less strength.
Use via stitching so impedance stays the same in all layers.
Keep reference planes under signal traces for good return paths and less extra capacitance.
Write down impedance needs, like stackup, copper weight, dielectric space, and target impedance.
Use CAD/CAM tools and impedance calculators to check the layout.
Test impedance with Time-Domain Reflectometry and test coupons that copy real boards.

If impedance is not matched right, some signal energy bounces back. These bounces make standing waves. Standing waves cause signal distortion, ringing, and more noise. These problems can make data errors and more signal loss. Matching impedance well lets more power move, stops bounces, and keeps signals strong. This is very important to lower signal loss in high-frequency PCB making.

Trace Design for High-Speed PCBs

Trace shape is important for lowering signal loss. Engineers pick trace width and space based on needed impedance and dielectric material. Wider traces lower resistance and insertion loss. Keeping space even helps keep impedance steady.

Surface finishes also change signal loss. The table below shows two common finishes:

Surface Finish	Advantages	Disadvantages Related to Signal Loss
ENIG	Flat surface, no lead, good for plated through holes, long shelf life	Causes signal loss at RF frequencies, expensive, not re-workable, black pad risk
OSP	Flat surface, no lead, simple process, re-workable, cost effective	Handling sensitive, short shelf life, no direct mention of signal loss

ENIG can make insertion loss worse at high frequencies. OSP does not change signal loss much. Engineers pick the finish based on what the PCB needs and the signal quality they want.

Differential routing sends two opposite signals at once. This cancels noise and makes the signal stronger. It also lowers crosstalk and keeps signals clear. Matching the length of differential pairs helps signal quality and lowers signal loss.

Managing Crosstalk and EMI

Crosstalk and EMI can hurt signal quality and raise signal loss in high-frequency PCBs. Ground planes give a good path for signals to return. This keeps impedance low and cuts down EMI. Putting signal layers between ground planes holds in electromagnetic fields and keeps signals strong.

Engineers use via stitching to link ground planes on different layers. This keeps impedance even and lowers ground bounce. Not splitting ground planes stops more electromagnetic radiation and helps the board work well.

Shielding, like metal shields and stitching vias around the edge, also cuts crosstalk and EMI. These ways help keep signals clear and lower insertion loss in fast PCB designs.

Tip: Put ground transition vias close to signal vias. This keeps electromagnetic fields in and helps control EMI.

Manufacturing and Testing with LT CIRCUIT

LT CIRCUIT uses new ways to make high-frequency PCBs with care and accuracy. The company checks quality at every step, from picking materials to final tests. Engineers use CAD/CAM tools and impedance calculators to design stackups that keep impedance even and signal loss low.

LT CIRCUIT gives many surface finishes, like ENIG and OSP, for high-speed and high-frequency PCBs. The company uses flying probe tests, E-tests, and Time-Domain Reflectometry to check impedance and insertion loss. These tests make sure each PCB meets tough rules for signal quality and efficiency.

By using good materials, careful design, and strong testing, LT CIRCUIT makes high-frequency PCBs with low signal loss and great signal quality. Customers get boards that work well and support fast digital circuits and high-frequency signals.

Engineers keep signals strong by picking special materials, planning the PCB stackup well, and making the boards carefully. The tables below show real examples and mistakes to avoid:

Project/Application	Issue Addressed	Strategy Applied	Result Achieved
5G Antenna Design	High signal attenuation at 28 GHz	Switched plating from ENIG to Immersion Silver	Signal attenuation reduced by 15%, improving antenna efficiency
10 Gbps Ethernet Board Design	7% impedance mismatch due to uneven ENIG plating	Used thinner Immersion Silver layer and optimized via design	Reduced reflections and resolved impedance mismatch

Common Pitfall	Cause/Effect	How to Avoid / Solution
Inadequate Power Distribution	Voltage drops, noise, instability	Use wide traces or planes for power; put decoupling capacitors close to power pins; keep power and ground planes low-impedance and continuous.
Incorrect Trace Widths	Excessive resistance, voltage drops, overheating	Figure out trace widths using current, temperature, and voltage drop; use PCB design tools to help.
Poor Signal Integrity	Crosstalk, EMI, signal degradation	Make high-speed traces short and straight; route over solid ground planes; use controlled impedance traces and differential pairs; keep enough space between traces.
Inadequate Grounding	Noise, interference, unstable operation	Use solid ground planes; add many ground vias; do not make ground loops to lower noise.
Neglecting EMC	Interference with other devices, regulatory failure	Add shielding, filtering, and grounding; do not use long parallel traces; keep loop areas small; test for EMC and check before final approval.

Checklist: Pick low-loss materials, match impedance, use the right trace widths, and test for signal strength. LT CIRCUIT helps with every step for good high-frequency PCB projects.

FAQ

What causes signal loss in high-frequency PCBs?

Engineers notice signal loss when the wrong materials are used. High insertion loss and bad pcb design also cause problems. High-frequency signals get weaker from signal attenuation. Signals can also weaken if impedance is not even across the board.

How do low-loss materials help minimize signal loss?

Low-loss materials, like special rf pcb materials and low loss solder mask, help a lot. These materials lower insertion loss. They make signals stronger and help high-frequency pcbs work better. They are also good for radio-frequency uses.

Why is impedance control important for high-speed PCB design?

Keeping impedance the same in transmission lines is important. It helps the board work well and keeps signals clear. Good impedance control stops signal problems. It also helps high-speed digital circuits work right in high-frequency boards.