3.1 Stubby Antennas

There are mainly two kinds of external antennas: stubby antenna and whip-stubby antenna. A stubby antenna extrudes from a phone and does not have any movable parts. Earlier in the mobile phone's history, all stubby antennas were helix antennas made of copper wire or copper-coated steel wire (music wire). From the mechanical point of view, a helix antenna is the same as a spring coil and they can be cheaply made by the same machines and tools. When mass-produced, spring coils cost a few pennies a piece, so the helix antenna is a considerable cost-effective solution. A spring coil has a round cross-section, so a helix antenna normally possesses a column shape. That is why it has the name of “stubby.”

Latterly, stubby antennas have all kinds of cross-sections, many of them are not made of helix and they are meander line antennas made of flex circuits. From an electrical point of view, a helix antenna is similar to a meander line antenna. It is not too difficult to master meander line antennas when you know helix antennas well.