The Industrial Wi-Fi Shop Podcast – Ep. 28 Antennas K.I.S.S

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On with Episode 28!!

Who is MP Antenna?

MP Antenna, based in Elyria, Ohio, designs and manufactures patented multipolarized antennas engineered for reliable connectivity in challenging RF environments. Its antennas are particularly well suited to mobile and industrial applications, including autonomous vehicles, mining operations, warehouses, and other congested or highly reflective spaces where motion, changing orientation, and multipath can disrupt conventional antenna performance. With in-house engineering, customization, simulation, and an anechoic test chamber, MP Antenna helps customers select and integrate antennas tailored to their specific applications.

Let’s talk about the basics first!

Gain
- What does antenna gain actually mean?
- Higher gain does not mean the antenna amplifies the radio signal or creates additional power
- Gain generally comes from reshaping the coverage:
  - More energy in the desired direction
  - Less energy in other directions
  - Often a narrower beamwidth
- A high-gain omnidirectional antenna can flatten the vertical pattern, potentially creating poor coverage directly above or below it
- In an industrial environment, modest gain with more uniform coverage may outperform a high-gain antenna
- Gain applies on both transmit and receive

Questions:
- When does adding gain make an industrial Wi-Fi deployment worse?
- How trustworthy are gain numbers when comparing different manufacturers?
- What is the difference between gain and antenna efficiency?

Polarity
- The more precise RF term is polarization, although people sometimes say polarity
- Polarization describes the orientation and behavior of the antenna’s electric field
- Common forms include:
  - Vertical
  - Horizontal
  - Slant, such as ±45 degrees
  - Circular
  - Multi-polarized designs.
- Polarization mismatch creates loss
- Device orientation matters:
  - A rotating forklift.
  - A tilted handheld scanner.
  - A vehicle moving over changing grades.
  - An access point mounted incorrectly.
- Reflections from racks, machinery, walls, tanks, and the ground can alter a signal’s polarization

Questions:
- How much signal can we lose simply because two antennas are oriented differently?
- How can polarization diversity help when the endpoint’s orientation is unknown or constantly changing?
- Can polarization diversity compensate for poor antenna placement, or only make a good installation more resilient?

Horizontal/Vertical Beamwidth
- Beamwidth describes the angular width of an antenna’s main coverage lobe
- It is normally measured between the points where signal strength falls 3 dB below the peak—the half-power points
- Two dimensions are usually specified:
  - Horizontal beamwidth: coverage around the antenna in the azimuth plane
  - Vertical beamwidth: coverage above and below the horizon in the elevation plane
- An omnidirectional antenna is approximately 360 degrees horizontally, but it is not omnidirectional in every direction
- Use the “donut” analogy carefully:
  - A basic vertical omnidirectional antenna resembles a donut
  - Increasing gain often makes that donut wider and flatter
  - Real patterns are less perfect than the textbook drawing
- Directional antennas concentrate energy into a sector or beam
- Narrow beamwidth can:
  - Extend useful range
  - Reduce unwanted RF from other directions
  - Require more accurate alignment
- Beamwidth should match the physical geometry of the application,not merely the desired distance
- Mounting height and vertical separation can matter as much as horizontal distance

Questions:
- Why isn’t a 360-degree omni also 360 degrees vertically?
- How do gain and beamwidth trade against one another?
- When should we choose a sector or directional antenna instead of an omni?
- How precise does antenna aiming need to be in a real industrial installation?

VSWR/SWR
- SWR means standing-wave ratio; VSWR means voltage standing-wave ratio
- In typical antenna discussions, the terms are often used interchangeably
- VSWR indicates how well the antenna system’s impedance matches the transmission line and radio
- A perfect match is 1:1, although no real broadband installation remains perfect under every condition
- Common reference points:
  - 1.5:1: generally a very good match
  - 2:1: commonly considered acceptable in many systems
  - Higher values mean more energy is being reflected toward the transmitter
- A 2:1 VSWR corresponds to approximately:
  - 11% reflected power
  - 0.5 dB mismatch loss
  - About 9.5 dB return loss
- An antenna can show a good match but still have:
  - Low efficiency.
  - Poor radiation pattern
  - Incorrect polarization
  - Unsuitable beamwidth
  - Lossy cabling
- VSWR can change when the antenna is installed near:
  - Metal
  - Concrete
  - Machinery
  - A vehicle body
  - An undersized ground plane
  - Other antennas

Questions:
- Can an antenna have a great VSWR and still perform badly?
- Why can an antenna test well on the bench and change after installation?
- How much can cables, adapters, or damaged connectors affect the reading?
- Where should VSWR be measured, at the antenna or at the radio end of the cable?

Antenna Patterning
- An antenna pattern is a map of how strongly an antenna transmits or receives in different directions
- Patterns should ideally be understood in three dimensions
- Data sheets commonly reduce the pattern to two cuts:
  - Azimuth or horizontal plane
  - Elevation or vertical plane
- Important pattern features include:
  - Main lobe
  - Side lobes
  - Back lobe
  - Nulls
  - Front-to-back ratio – primarily Yagi and other directionals
  - Beamwidth
- Coverage is rarely a perfect circle, cone, or donut
- Pattern charts are often normalized to the antenna’s peak, so they show relative directionality rather than actual received signal strength at a specific distance
- A polar plot’s scale matters. A plot using 5 dB divisions can look dramatically different from one using 10 dB divisions
- Check whether a published pattern represents:
  - One frequency or the entire band
  - One polarization or multiple polarizations
  - A free-space test or an installed configuration
  - A simulated or measured result
- Pattern shape can change across 2.4, 5, and 6 GHz
- Mounting hardware, enclosures, ground planes, nearby metal, and cable routing can distort the pattern

Questions:
- How should a Wi-Fi engineer read a polar plot without being an antenna engineer?
- Which matters more in a moving industrial application: peak gain or pattern consistency?
- What should listeners look for when a data sheet shows only one polished-looking pattern?
- How much does the pattern change across a wide frequency band, like 6GHz for example?

If you would like to connect with Ben or learn more about his employer, MP Antenna, then check the following:

Ben Baranek – https://www.linkedin.com/in/ben-baranek-7b0b63293/

MP Antenna – https://www.mpantenna.com/

If you would like to connect with Brent or learn more about his employer, MP Antenna, then check the following:

Brent Miller – https://www.linkedin.com/in/brent-miller-05457447/ .

MP Antenna – https://www.mpantenna.com/

If you would like to connect with Scott or learn more about his employer, Global Process Automation (GPA), then check the following:

Scott McNeil – https://www.linkedin.com/in/americanmcneil/

GPA – https://www.global-business.net/

If you would like to connect with Jeremy or learn more about his employer, Prism Systems Inc, then check the following:

Jeremy Baker – https://www.linkedin.com/in/jeremyabaker/

Prism Systems Inc – https://www.prismsystems.com/