What a Wi-Fi Antenna's Radiation Pattern Reveals: A Complete Analysis for Home and Office Networks

When you buy a Wi-Fi router or external antenna, manufacturers often include a mysterious "radiation pattern" in the specifications. At first glance, this is simply a graph with curves and numbers, but in reality, it's the key to understanding how the signal will propagate in your room. Without properly interpreting this pattern, you risk wasting money on equipment that either won't cover the required area or will create "dead" zones where the signal is critical.

In this article, we will look at what exactly the radiation pattern shows, how to read it for different types of antennas (omnidirectional, sectorial, panel), and How to use this data to optimize your Wi-Fi network in an apartment, house, or office. You'll learn why the same antenna can produce different results in the horizontal and vertical planes, how polarization affects it, and what technical nuances Often missed by even experienced network administrators.

What is a radiation pattern and why is it needed?

The radiation pattern of an antenna is a graphical representation of how how an antenna transmits or receives a radio signal in spaceIt shows in which directions the signal is strongest, and where it weakens or disappears completely. Without this graph, you're choosing an antenna "blindly," relying only on the stated power in dBi, which often leads to disappointment.

For example, if you install omnidirectional antenna in the corner of the room, the diagram will show that half of its "power" goes into the wall, and not into the room. Or let's take sectorial antenna: Its pattern may have 120° gain "lobes", but if you point it wrong, the coverage will be worse than that of a cheap "rubber band" from a router.

• 📡 For users: helps you choose an antenna for a specific task (for example, covering a long corridor or a two-story house).
• 🛠️ For installers: shows how to properly orient the antenna physically (horizontally/vertically) and where to place the access point.
• 📊 For diagnostics: explains why the signal is weak in some areas despite a "powerful" router.

Important: The diagram is always linked to specific frequency (For example, 2.4 GHz or 5 GHz). The same antenna can behave differently on different bands! This is often overlooked when comparing antennas solely by appearance.

Basic Chart Parameters: What the Lines and Numbers Mean

Let's look at the key elements of a chart using a typical chart as an example. omnidirectional antenna (For example, TP-Link TL-ANT2406A). Typically the diagram is a polar plot, where:

• 🔄 Center of the circle - this is the position of the antenna.
• 📏 Radius shows the signal level (usually in decibels, dB). The further the line is from the center, the stronger the signal in that direction.
• 🌐 Angle (0°–360°) — direction of radiation relative to the antenna.

On the graph you will see one or more curves. For example:

• Solid line — radiation in the horizontal plane (azimuth).
• Dotted line — radiation in the vertical plane (elevation).

A critical detail: if the diagram shows a gain of 9 dBi, this does not mean the signal will be 9 times stronger in all directions. The gain is achieved by narrowing the beam—that is, the antenna "collects" energy in one direction, attenuating it in others.

⚠️ Attention: Some manufacturers provide diagrams only for ideal conditions (antenna in an anechoic chamber). In real-world environments, the signal will be distorted due to reflections from walls, furniture, and metal objects. Always allow for some coverage!

Antenna types and their patterns: a comparative analysis

Directional patterns vary dramatically depending on the antenna type. Let's look at the three most common types found in home and office networks.

1. Omnidirectional antennas (rubber bands on routers)

Ideal for covering all directions around an access point (for example, in the center of an apartment). Their pattern looks like a circle with small "dents." Typical models: D-Link ANT24-0700, ASUS WiFi Antenna.

• ✅ Pros: easy installation, even coverage.
• ❌ Cons: weak signal over long distances, some energy is wasted in unnecessary directions (for example, into the ceiling).

2. Directional antennas (panel, yagi)

They have a narrow beam with high gain in one direction. Examples: Ubiquiti LiteBeam M5, TP-Link TL-ANT2424BThe diagram resembles a "petal" with a width of 30°–60°.

• ✅ Pros: long-range signal (up to several kilometers in open areas).
• ❌ Cons: Requires precise angle adjustment, not suitable for multi-room spaces.

3. Sectoral antennas

A compromise between omnidirectional and directional. They cover a 60°–120° range with 10–15 dBi gain. Popular in offices and hotels. Example: MikroTik Sector Antenna.

• ✅ Pros: good coverage in a given sector, less interference from neighboring points.
• ❌ Cons: More expensive than omnidirectional ones, requires correct orientation.

Why can high gain antennas (15+ dBi) degrade communication?

These antennas have a very narrow beam. If a client device (such as a smartphone) moves outside this beam even by a small angle, the signal will drop sharply. Furthermore, high gain is often achieved at the expense of narrow vertical coverage, which leads to problems on different floors.

Which type should you choose? It depends on the task:

• 🏠 Apartment: omnidirectional or sectorial (if the router is near the wall).
• 🏢 Office: sectorial antennas with overlapping zones.
• 🌳 Street (dacha, cottage): Directional antennas for point-to-point communication.

How to Read a Chart: A Step-by-Step Guide

Let's take a real radiation pattern (for example, for an antenna Ubiquiti UniFi AC Mesh) and let's analyze it step by step.

Step 1. Find the principal direction of radiation.

On the graph, this will be the "longest" lobe. For example, if the maximum signal occurs at 0°, this means the antenna should be oriented "facing" in that direction.

Step 2: Estimate the beam width.

Look for points where the signal weakens by 3 dB from its maximum. For example, if the graph says "Beamwidth: 60°," this means the signal remains stable within ±30° of the center.

Step 3: Check the side petals.

These are small "bursts" of signal outside the main beam. They can interfere with other devices or, conversely, help cover additional areas (for example, an adjacent room).

Step 4: Compare the horizontal and vertical planes.

Many antennas (especially panel antennas) have different patterns in these planes. For example, TP-Link TL-ANT2424B It produces a 60° beam in the horizontal plane and only 15° in the vertical plane. This means that the antenna covers the area well. in width, but badly - in height (not suitable for two-story houses).

⚠️ Attention: If you see sharp signal dips on the diagram (for example, -20 dB in one direction), this may indicate a defective antenna or a measurement error. Normally, the curve should be smooth.

Practical Application: How to Use a Diagram to Configure a Network

Now that you know how to read a diagram, let's look at how to apply this knowledge in practice.

1. Optimal router placement

If you have an omnidirectional antenna:

• 📍 Place the router in the center of the room, away from walls and metal objects.
• 📏 Raise it to a height of 1–2 meters (at the level of a table or shelf).

For directional antenna:

• 🎯 Point the main blade towards the area where maximum speed is needed (for example, a work desk).
• 🚫 Avoid orienting the antenna towards walls or windows (the signal will be absorbed).

2. Choose between 2.4 GHz and 5 GHz

The charts for these ranges can vary greatly! For example:

• 📶 On 2.4 GHz The signal bypasses obstacles better, but is susceptible to interference from neighboring networks.
• 📶 On 5 GHz The pattern is usually narrower (less coverage), but the speed is higher and there is less interference.

3. Solving weak signal problems

If the signal is weak in some area, check:

• 🔍 Is this zone located in a "dead" zone of the diagram (for example, behind a directional antenna).
• 🔄 Is the signal being blocked by the side lobes of another antenna (if you have multiple access points).
• 📡 Are there any obstacles (concrete walls, metal cabinets) that are not taken into account in the diagram.

Example: if you have sectorial antenna With a 90° coverage angle, and the router is in the corner of the room, half the signal is lost to the wall. The solution is to rotate the antenna 45° or use a reflector (for example, a sheet of foil behind the antenna).

Common mistakes when working with diagrams

Even experienced users sometimes make mistakes when interpreting diagrams. Here are the most common ones:

1. 🔢 Ignoring the vertical plane. Many people look only at the horizontal beam pattern, but for two-story houses, the vertical beam is also critical! For example, an antenna with a narrow vertical beam (10°) won't cover the second floor, even if the horizontal beam is wide.
2. 📊 Comparison of antennas by gain (dBi) only. A 12 dBi antenna can have a narrower beam than a 6 dBi antenna and as a result cover smaller area.
3. 🔄 Failure to take polarization into account. If the router antenna is vertically polarized and the client device antenna (for example, a USB adapter) is horizontal, the signal will be weakened by 20–30 dB!
4. 🏗️ Neglect of real conditions. The diagram is recorded in an anechoic chamber, and in an apartment, the signal reflects off walls, furniture, and even aquariums. Always allow for some power reserve.

⚠️ Attention: Some Chinese manufacturers overstate the parameters in their diagrams (especially for cheap antennas on AliExpress). If the actual gain differs from the stated one by more than 2 dBi, this is grounds for returning the item.

Programs and tools for diagram visualization

If you want to do more than just read diagrams, but also model network coverage, use these tools:

It's enough for home use. WiFi Analyzer or NetSpotThese programs will show the actual signal level in different rooms, and you can compare it with the theoretical diagram.

Example: if the diagram promises 120° coverage, but in practice the signal disappears at 90°, this could mean:

• 📵 Interference from neighboring networks (check in WiFi Analyzer channel congestion).
• 🧱 Strong signal absorption by walls (concrete weakens the signal by 10–15 dB!).
• 🔋 Antenna or cable faulty (check connections).

FAQ: Frequently Asked Questions about Polar Patterns

🔍 Why does my 9 dBi antenna have a weaker signal than the standard 3 dBi antenna?

Most likely your antenna has narrow radiation pattern, and you're outside the main lobe. High-gain antennas "collect" the signal into a narrow beam, so if you're outside this beam, the signal will be weaker than with an omnidirectional antenna. Check the antenna's orientation and its pattern.

📡 How do I know what polarization my antenna has?

Polarization is usually specified in the antenna specifications (vertical, horizontal). If not specified, look at the physical orientation of the antenna elements:

• If the antenna "sticks" are located vertically — vertical polarization.
• If "sticks" horizontal — horizontal polarization.

For maximum efficiency, the antenna polarization of the router and client device must match.

🏠 Can a directional antenna be used to cover an entire apartment?

Technically it is possible, but it is not optimal. Directional antennas (for example, yagi or panel) have a narrow beam (30°–60°), so they will only cover part of the room. For an apartment, it's better to:

• Use omnidirectional antenna in the center of the apartment.
• Or combine several sectorial antennas (for example, 2-3 antennas at 120°).
• Or install Mesh system (For example, TP-Link Deco), which automatically optimizes coverage.

📵 Why does the signal disappear when I move 1–2 meters?

This is typical for antennas with very narrow diagram (e.g. 10°–20°). Even a small offset can move the device out of the main lobe zone. Solutions:

• Use an antenna with a wider beam (e.g. 60° instead of 30°).
• Check if metal objects or other Wi-Fi networks are interfering with the signal.
• Make sure the antenna is oriented correctly (sometimes turning it by 5°–10° is enough).

🛠️ Is it possible to change the antenna pattern myself?

Yes, but within limits. Here are a few ways:

• 🔄 Reflectors: Place a metal sheet (such as foil on cardboard) behind the antenna. This will strengthen the signal in one direction at the expense of weakening it in the opposite direction.
• 📡 Antenna combination: Use multiple antennas with different patterns (for example, one directional for outdoors and one omnidirectional for indoors).
• 🔧 Angle adjustment: Experiment with tilting the antenna - sometimes changing the angle by 10°–15° will significantly improve coverage.

However, it is impossible to radically change the diagram (for example, to make an omnidirectional antenna directional) - this requires a different design.