The subject of antenna measurements is one which has undergone revolutionary changes in recent years, in particular within space applications, where high demands are placed upon antenna design and construction. This book represents the specific measurement technique known as the spherical near-field method. The theoretical treatment of the method is detailed but of sufficient generality to make the book useful as a basis for further research on near-field measurements and antenna coupling problems. Practical aspects of antenna test ranges, data processing schemes and measurement procedures are described. Other topics covered are measurement error analysis and generation of plane wave fields. The authors draw on the experience from the development, sponsored by the European Space Agency, of one of the first spherical near-field test ranges. They have contributed to the establishment of spherical near-field testing as a highly accurate and versatile method, currently under implementation at test ranges worldwide.