All three 2020 iPhone models expected to have 5G wireless connectivity
Apple analyst Ming-Chi Kuo expects a trio of iPhones in 2020, and revising a previous prediction, he now thinks that all three will have 5G, instead of just two of them.

The rear cameras on dummy models of Apple's expected new iPhones, with a similar design expected for 2020. Render by Benjamin Geskin
In a research note, Ming-Chi Kuo from TF Securities cites competition from 5G adoption in high-end Android phones, forcing the revision from Apple. As a result of the proliferation, Kuo believes that consumer sentiment will demand that all of the 2020 models have the technology.
What isn't yet certain is if Apple will release a 5G phone without mmWave technologies for some markets like China that only will support sub-6GHz networks. Kuo believes that "Apple and EMS who are currently focusing on developing and testing mmWave may not have enough development resources if Apple would like to develop the 5G iPhone, which will only support Sub-6GHz."
For 5G specifically, frequencies can be generally categorized into one of two groups -- low-frequency sub-6GHz bands, and higher-frequency 6GHz bands. The first low range consists of bands that are currently used for existing mobile network communications, as low as 600MHz and up to 2,600MHz, though it can also include "C-Bands" up to 4,700MHz.
The 6GHz band is referred to as mmWave in the US. It is the part of the 5G specification that delivers the fast speeds -- assuming that a handset is within the short range of a mmWave transmitter.
Rumors have suggested that Apple will use a smaller TrueDepth camera -- allowing it to shrink the notch on OLED screens -- plus a seven-piece lens system for the rear camera. A more questionable claim is that there could be a China-exclusive model that switches out Face ID for subscreen Touch ID.
A recent rumor suggests that the Taptic Engine responsible for all of the iPhone haptics will see a revision in 2019, and carried along to the 2020 iPhone.
It is generally believed that Apple will have three models, all of them OLED-based, in 5.4-, 6.1-, and 6.7-inch sizes. Kuo previously believed that the 6.1-inch unit would forego 5G support, relegating it to mid-tier status like 2018's iPhone XR

The rear cameras on dummy models of Apple's expected new iPhones, with a similar design expected for 2020. Render by Benjamin Geskin
In a research note, Ming-Chi Kuo from TF Securities cites competition from 5G adoption in high-end Android phones, forcing the revision from Apple. As a result of the proliferation, Kuo believes that consumer sentiment will demand that all of the 2020 models have the technology.
What isn't yet certain is if Apple will release a 5G phone without mmWave technologies for some markets like China that only will support sub-6GHz networks. Kuo believes that "Apple and EMS who are currently focusing on developing and testing mmWave may not have enough development resources if Apple would like to develop the 5G iPhone, which will only support Sub-6GHz."
For 5G specifically, frequencies can be generally categorized into one of two groups -- low-frequency sub-6GHz bands, and higher-frequency 6GHz bands. The first low range consists of bands that are currently used for existing mobile network communications, as low as 600MHz and up to 2,600MHz, though it can also include "C-Bands" up to 4,700MHz.
The 6GHz band is referred to as mmWave in the US. It is the part of the 5G specification that delivers the fast speeds -- assuming that a handset is within the short range of a mmWave transmitter.
Rumors have suggested that Apple will use a smaller TrueDepth camera -- allowing it to shrink the notch on OLED screens -- plus a seven-piece lens system for the rear camera. A more questionable claim is that there could be a China-exclusive model that switches out Face ID for subscreen Touch ID.
A recent rumor suggests that the Taptic Engine responsible for all of the iPhone haptics will see a revision in 2019, and carried along to the 2020 iPhone.
It is generally believed that Apple will have three models, all of them OLED-based, in 5.4-, 6.1-, and 6.7-inch sizes. Kuo previously believed that the 6.1-inch unit would forego 5G support, relegating it to mid-tier status like 2018's iPhone XR
Comments
This way Apple can avoid the Galaxy Fold mess & the Note 7 (banned on planes) disaster.
The iPhone XR (LCD/FaceID) will be good low end iPhone, with only “refurbished” below that, sold in the USA. I think Apple wants to move to FaceID/AR phones as quickly as possible to get people on services like Apple Arcade.
Apple’s biggest problem is high end. I see value in OLED... but a better camera & faster processor & 5G? Does anyone really “need” that? I can see it on the iPads, but phones... not so much. The phone market is really mature, which is why Apple is focusing on services...
I expect a greatly shrunken “notch” so perhaps styling will drive new phone adoption.
If there is a wireless plan that caps performance to 4G speeds, even though your running on a 5G network, that might be a great “value”.
Paying up for 5G speeds is probably a waste. It will be interesting to see how carriers handle data caps, you could blow through 100GB of data at 5G speeds in a day...
Bottom line, if you have a iPhone you’re happy with, waiting a year might make sense. Especially, if reception isn’t the best in your area...
I don’t think it is really any big surprise Apple now plans on going all 5G, considering the recent shifts in their menthods and the clear competition that is going to be there in a while.
As for the other portions of 5G, it's possible that they may give better reception. It's also possible that the infrastructure upgrades will yield improved 4G performance, and honestly, I can count on one hand the number of people I know who truly feel they need more than a good 4G signal.
Either way, 2020 is about right. It will be at least then before there is really any 5G coverage to speak of, and well beyond that before there is actually and true use for 5G.
because they needed time to actually develop the phone? It does involve a bit more than just swapping out the chip.
The jury is not out. This is also bullshit scaremongering by quack sources.
MMWave is going to be very rare for the foreseeable future. If you believe that MMWave (which is a radio wave) causes cancer, then you must also believe that microwaves, radio/tv waves, cellular communication, speakers, bluetooth, ham radios and anything else that emits radio waves causes cancer as well. Apparently cancer was unknown until radio was invented ...
So the good news is that you don't have to worry about it. Unless you live in the heart of a large major city, it's likely to be a half-decade or more before you're even using (any sort of) 5G, and even then 90 percent of the time it will be the sub-6GHz (non-MMWave), because that's the version that actually works the way LTE does, since it's using the same frequencies.
If you're still scared of MMWave, just hide behind a door -- MMWave can't penetrate any obstacles (trees, rain, walls, etc).
The "Millimetre Wave" sort of 5G using much higher frequencies -- frequencies that have not been exploited for mass communication until now. It's waaaaaay faster, but extremely short range and prone to easy blocking by almost any sort of obstacle (even rain). This sort will mostly be available only in wide-open areas, like between the roofs of two nearby buildings for example.
The aforementioned article if you'd like to see the information in detail: https://appleinsider.com/articles/19/05/01/what-is-5g-and-mmwave-and-when-will-you-be-able-to-realistically-use-it
In in the long term, once Apple does its own 5G I would expect in an iPad Pro first so it doesnt have to worry about voice, data only as a first step.