Cad and Mechanical Realization of Planar, Ka-Band, 8x8 Butler Matrices

Abstract

Butler matrices of order four (4x4) have been recently investigated concerning their electromagnetic modelling, mechanical/thermal design and actual realization. However, from a practical viewpoint, planar Butler matrices of order eigth (8x8) are the minimal to be considered for e®ective graceful degradation when using multiport ampli¯ers. The transition from 4x4 planar Butler matrices to 8x8 con¯gurations is by no means trivial, due to the large increase in components' number and crossings. Moreover, while at X and Ku-bands mechanical tolerances are a relatively small problem, manufacturing of matrices for applications at higher frequencies such as at Ka-band adds a further di±culty. In this paper we describe a planar 8x8 Butler matrix baseline layout and a possible arrangement for realizing such a high complexity network in a compact manner. A prototype operating at Ka-band has been designed, implemented in reduced height waveguides, and measured, showing very good performances.

Ultrabroadband 8 × 8 Butler matrix designed with the use of multisection directional couplers and phase correction networks

“…8 × 8 and higher order matrices are rarely reported, however, some examples of 8 × 8 Butler matrices developed in different technologies can be found [14–16]. In Ref.…”

Planar reconfigurable antennas for satellite communications

“…The problem with these antennas is that they do not have the necessary directivity since each beam only uses a reduced number of radiating elements. Another way to have a multibeam antenna is using a steering network such as a Butler network (see [62] and [63]). These networks can have similar losses than commercial phase shifters but they take up more space.…”