Signal Strength and Phone Cases: What You Need to Know

Phone cases offer the ultimate protection for your device, shielding it from bumps, drops, scratches, and anything else that comes its way. It’s almost hard to believe that they could have any drawbacks.


But then you look at your screen and see one lonely bar – and your signal drops. It can’t possibly be your phone case…right? Do phone cases block signal?


Some claim that cell phone cases do block signal, while others have dismissed it as a myth. Don’t know which to believe? Today, we’re uncovering the truth about signal strength and phone cases.

Understanding Signal Interference

Can a metal phone case block signal? Can a cell phone case interfere with reception? Before we tackle your burning questions you have to understand how signal strength works.


Phones communicate via radio frequency, transmitting radio waves from their (internal) antennas to the nearest cell tower. If your phone allows these radio waves to be transmitted, you’ll have good signal strength. Poor signal strength can affect call reception, internet connectivity, and prevent your texts from going through.


Signal can be blocked by phone cases or anything that’s not “radio transparent”, which basically means anything that doesn’t allow radio waves to pass through. Here are a few of the common things that can interfere with your signal.


Phone Cases: When it comes down to it, phone cases can block signal – but this doesn’t apply to every phone case. Poorly designed cases that block your phone’s antenna and cases made out of certain materials are the biggest culprits.


Weather: Dealing with no signal on a stormy day? Adverse weather conditions, like rain, fog, wind, and even high humidity can affect signal strength. That’s because water is conductive – it conducts electricity, allowing water vapor in the atmosphere to reflect and refract the radio waves needed for a strong signal.


Thick Vegetation: Mountains, forests, and those secluded hiking locales make the perfect backdrop for your photography. But unfortunately, they can also block radio waves. The quick photo edits and posting will have to wait!


Network Traffic: More common in densely populated areas, network congestion can hinder your signal or make it nonexistent.


Buildings and Windows: You may already know that dense building materials like concrete, brick, and steel can block signals, but windows can do the same! Energy-efficient windows found in some buildings contain a metal oxide coating that helps control room temperature. The only downside is that this coating can also repel signals!

How Phone Cases Can Affect Signal Strength

Do cell phone cases block signal? In some instances, yes. It comes down to two things: the materials used and the case design.

Phone Case Materials

Not all cell phone cases interfere with reception. It depends on the material your phone case is made of. There are conductive and non-conductive materials that can be used, which impacts your signal strength:

 

Conductive Materials: Conductive materials make it difficult for your phone to effectively transmit radio waves. Radio waves can’t pass through these electrical conductors, and this can diminish your signal strength. Conductive cases might be made with materials like metal, aluminum, and copper.

 

Non-Conductive Materials:  Materials like silicone, polycarbonate, and rubber don’t interfere with reception. Because of this, most phone cases are made with these non-conductive materials.


Material alone is not the only indicator of whether or not your cell phone case will block the signal; you also need to consider the design. 

Phone Case Design

No need to throw away your current protective phone case just yet! Keep in mind that it’s only poorly designed cases you need to avoid to maintain a strong signal. What should you look for when it comes to good phone case design?


Thin Design: You don’t want an overly thick phone case – even if it’s made of a non-conductive material like silicone. This could also reduce your signal strength.


Antenna Line Design: Remember, phones have antennas that transmit radio waves and communicate with cell towers. They have trouble passing through anything that doesn't let radio waves pass through – like conductive materials. 


If you want a metal case, look for a design with antenna lines. These are typically plastic lines that function as signal transmitters. Without them, any metal phone case or phone case made using an electrical conductor can block your phone’s signal.

 

Maintaining Signal Strength

Some types of phone cases may block signal but that doesn’t mean you should lose the case entirely. Follow these tips to salvage your signal strength:

Troubleshoot the Problem

Struggling with a poor signal? It’s time to troubleshoot! Go into another room or outside, restart your phone, and/or toggle airplane mode on and off to see whether your signal improves. 


Still nothing? Phone cases do block signals sometimes, so take off your phone case and see if it improves. If it does (and there’s not heavy network traffic in your area), it may be time for a new case!

Avoid Metal Cases

Since a metal case can block signal, you might not want one on your phone. They’re generally not recommended because they’re electrical conductors.


Look for a phone case made of a non-conductive material instead, like polycarbonate or silicone. If you have to have metal, make sure it features a design that doesn’t get in the way of signal (e.g., antenna lines).

Maximize Your Signal Strength

Do cell phone cases block signal? Can a cell phone case interfere with reception? A metal case or poorly designed case can block signal, but you don’t need to worry if you have a high-quality case from a trusted manufacturer like ZAGG.


At ZAGG, we offer the thinnest and strongest protection so you can feel confident in your device’s performance, plus, we have the stylish designs and charging accessories you’ll love. Protect better!

FAQs

Made to shield against damage, it’s understandable many are concerned that they shield against something else entirely: signal strength. However, most cell phone cases do not block your signal or reception if they’re made from plastic, silicone, and leather. That’s because these materials can’t block or absorb any reception.
While most phone case materials won’t interfere with your signal, the same can’t be said for metal phone cases. These phone cases do block signals. Why? Radio waves can’t pass through electrical conductors like metal and metal alloys, meaning your signal will be seriously degraded. For that reason, you may want to avoid metal cases, clips, and attachments on your phone.
Since a cell phone case can interfere with reception (e.g., metal cases), you want to make sure you’re not one of the unlucky few. To test your theory, remove your phone case, restart your phone, or go into another room or outside, and check to see if any of these tests impacted your signal. Just remember that other factors can affect signal too, such as your location, weather, or obstructions like buildings and even network traffic.
A low-quality, poorly-designed phone case manufactured using metal is the last thing you want if you’re looking for a better signal from your phone. Instead, you want to choose a well-designed phone case from a trusted manufacturer that’s made from a material like silicone or recycled plastics. These are great phone cases that do not block signal.
If your phone is showing a weak signal, try going into another room, upstairs (if applicable), or outside. Trees, buildings, and walls can all affect your signal. You could also toggle airplane mode – which restarts cellular network modems –, restart your phone, or take off your phone case. A metal phone case can block signal, so be sure you buy a phone case in another non-conductive material from a trusted manufacturer like ZAGG.

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