William Alan Stewart Butement CBE (18 August 1904 – 25 January 1990) was a New Zealand-born British-Australian defence scientist and public servant.

A native of New Zealand, he made extensive contributions to radar development in Great Britain during World War II, served as the first chief scientist for the Australian Defence Scientific Service, then ended his professional career with a research position in private business.

A breadboard test unit, operating at 50 cm (600 MHz) and using pulsed modulation, gave successful laboratory results, but was not of interest to War Office officials.

By 1936 they had moved to the Bawdsey Manor Research Centre (on the North Sea coast) and had already begun plans for deployment of the CH system.

Referred to as Range and Direction Finding (RDF), Bawdsey had by this time begun branching out, forming teams to design and build all sorts of radar related devices.

At Bawdsey, Butement was assigned to develop a Coastal Defence (CD) RDF system to be used for aiming anti-shipping and anti-aircraft guns.

He also developed what became the standard method of determining miss-distance of gunfire against shipping by using RDF echoes from splashes caused by shells hitting the sea.

He completed the circuit design, but there was the problem of packaging such a device in a small projectile, as well as the question of the vacuum tubes surviving the acceleration forces at firing.

In February 1940, Harry Boot and John Randall at Birmingham University built a high-power cavity magnetron, allowing signal-generation at microwave frequencies.

Germany began bomber attacks on the British mainland, and it was decided that radar research and development activities would be moved further inland.

In 1943, Butement, then Assistant Director of Scientific Research with the Ministry of Supply, invented and supervised the development of a secure radio-based method of battlefield communication using narrow beams of pulsed microwave signals, to replace the traditional telephone cable.

The project included laboratory and workshop facilities at Salisbury, South Australia, and a rocket test range at a new town, Woomera, in the Australian Outback.

As a British subject, he was eligible to hold official positions in Australia, and, shortly after arriving, he was appointed Chief Superintendent of the project.

While by this time Butement was primarily a research administrator rather than a hands-on scientist, he did personally initiate several highly important developments, including a rocket engine that used a semi-solid paste pressed into the firing chamber as propellant, and the Malkara missile, an anti-tank guided weapon that was adopted as standard equipment by the Australian and British armies.

After retirement from Plessey in 1972, Butement remained in Melbourne where he was an enthusiastic amateur radio (ham) operator (call sign VK3AD) and an adept carpenter, metalworker, and mechanic.