Selecting the correct calibration kit to use with your VNA.

The calibration kit ordered for a vector network analyzer (VNA) should be chosen based on two main criteria, in order to select the correct model:

The connector on the devices you wish to test - commonly called the device under test (DUT). The connector type on your VNA is totally irrelevant when selecting a VNA calibration kit. The connector type on the VNA only dictates what RF/microwave adapters will be needed to connect between the VNA and the DUT.
The frequency range you wish to test devices to.

Selecting the right connector type on the calibration kit

If you only want to test SMA devices, but your VNA has N connectors, then you need an SMA calibration kit and do not need an N calibration kit. Many people make the mistake of thinking they need an N calibration kit if their VNA has N connectors. If you wish to test waveguide components, you need a waveguide calibration kit. Many of the older VNAs available, in particular the very popular HP 8753 series, have APC7 connectors on them. Despite being a precision connector, it use is relatively rare in 2024, so most people do not need an APC7 calibration kit, even if their VNA has APC7 connectors. The table below should help clarify this.

SMA, 3.5 mm and 2.92 mm(K) connectors are mechanically compatible. An SMA kit can calibrate SMA, 3.5 mm or 2.92 mm devices, although the upper frequency limit of 3.5 mm and 2.92 mm extends beyond that of SMA connectors. Generally SMA connectors are considered rated up to 18 GHz, 3.5 mm up to 26.5 GHz and 2.92 mm (K) up to 40 GHz

Connector on DUT	Connector on VNA	Suitable calibration kit
SMA	APC7	SMA
SMA	N	SMA
SMA	3.5 mm	SMA
SMA	SMA	SMA
SMA	2.92 mm or K	SMA
SMA	2.4 mm	SMA
N	APC7	N
N	N	N
N	3.5 mm	N
N	SMA	N
N	2.92 mm / K	N
N	2.4 mm	N
3.5 mm	APC7	SMA
3.5 mm	N	SMA
3.5 mm	3.5 mm	SMA
3.5 mm	SMA	SMA
3.5 mm	2.92 mm or K	SMA
3.5 mm	2.4 mm	SMA
WR90 Waveguide	APC7	WR90 Waveguide
WR90 Waveguide	N	WR90 Waveguide
WR90 Waveguide	3.5 mm	WR90 Waveguide
WR90 Waveguide	SMA	WR90 Waveguide
WR90 Waveguide	2.92 mm / K	WR90 Waveguide
WR90 Waveguide	2.4 mm	WR90 Waveguide

Kirkby Microwave sell calibration kits for SMA (our most popular), N and waveguide calibration kits. Waveguide kits tend to be built to order, so please contact us about those.

Selecting the right frequency range for the calibration kit

Kirkby Microwave sell the following ranges of kits as standard.

SMA up to 7 GHz. The Kirkby Microwave 85033 7 GHz SMA calibration kit is is our most common standard product.
SMA up to 8, 9, 10, 11 GHz or 12 GHz are available to special order. Please contact us
N 18 GHz. The 85054 kit is an 18 GHz kit, although to keep costs down, it is usually supplied with loads suitable only to 6 GHz. For use above 6 GHz, different loads are required. Please contact us for more information about N kits with 18 GHz loads, as these are not always available.

Kirkby Microwave Ltd is registered in England and Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Essex, CM3 6DT.