MHF4 to SMA Cables for Antennas

MHF4 connectors

The MHF4 connector is the world's smallest radio frequency connector in the world with a mated height of only 1.2mm (0.047 inches). Its extremely low profile and PCB connectivity make it useful in applications that have a component-dense environment.

Characteristics of the MHF4 connector

This 50-ohm connector can support frequencies up to 6 GHz and a maximum voltage of 60 volts.

• Male jack: The PCB-mounted male jack is made from LCP-coated PBT with a gold-plated ground contact. The center pin is made from silver or gold-plated phosphor bronze.
• Female plug: The female plug is made from a gold-plated copper alloy and mates with a press-down action and needs to be lifted vertically off to be disconnected.

The MH4 connector is rated for a maximum of 30 mating cycles. It can be connected by hand or using a special push-pull tool to prevent damage to the connector.

Applications of SMA to MHF4 cables and adapters

Both the SMA and MHF4 connectors are used in wireless, IoT and telecommunications technologies that include:

• Wi-Fi
• Bluetooth
• Cellular
• GPS

The small size of the MHF4 connector means that it is present in a wide range of range of wireless devices, while the SMA connector is routinely externalized for the easy and repeated connection of antennas and cables.

SMA to MHF4 pigtail adapters

SMA to MHF4 pigtail adapters are made with a length flexible micro coax connecting the MHF4 connector and larger, externalized SMA connector. Here are the specifications of 1.13 mm coax the pigtail adapter uses:

• Diameter of 1.13mm (0.04 inches) / AWG of 32.
• Silver-plated annealed copper center conductor and non-polymer dielectric.
• Copper polyester tape as an insulating binder to enhance shielding.
• FEP jacket.
• Nominal impedance of 50 Ohms.
• Maximum frequency of between 6 and 8 GHz.
• low conductor resistance of 482Ohm/km.
• Insulation resistance of 3000 Ohm/km.
• VSWR is 1.3 between 0 and 6 GHz up to a maximum of 1.45 between 6 and 8GHz.

SMA connector specifications

The subminiature version A or SMA connector is a subminiature, semi-precision threaded radio frequency connector.

Physical specifications of the SMA connector

• Dimensions: the male connector has a diameter of 7⁄16 inches (11 mm) and the female connector has a diameter of 3⁄8 in (9.5 mm)
• Threading: 36 threads per inch
• Material: gold or nickel-plated machined brass with a Teflon insulator
• Male SMA connector: cylindrical body with internalized threads and outer hex-nut for tightening the mated connector with a wrench. Center pin conductor.
• Female SMA connector: cylindrical body with externalized threads, inner beryllium copper receptacle, and silicone rubber gasket

Electrical specifications of the SMA connector.

• Nominal impedance: 50 ohms
• Maximum frequency: up to 18 GHz
• Voltage rating: 500 volts.
• VSWR: 1.05 to 1.15 (depending on the attached coaxial cable)
• Contact resistance: 2.0 milliohms.
• Insertion resistance: 5000 megaohms.
• Radio frequency leakage: maximum of -90dB (at 2 to 3 GHz)

Mechanical characteristics of SMA connectors

• Mating: screw coupling tightened via male hex nut
• Vibration, moisture, and dustproof connection
• Mating cycles: 500+