An apparatus comprising: a spacecraft communications payload including a beam forming network, BFN, wherein: the BFN includes a first feed waveguide and a first set of branch waveguides (113; 513), each branch waveguide in the first set being configured to operate in a frequency band having a first characteristic waveguide wavelength λ g1; a proximal portion of the first set of branch waveguides is communicatively coupled with the first feed waveguide; a distal portion of the first set of branch waveguides comprises an array of slots and is communicatively coupled by way of the array of slots with a plurality of radiating elements (318; 418); the array of slots is configured as a honeycomb-like triaxial lattice having three characteristic axes (133, 134, 135), respective pluralities of slots being aligned with each of the three characteristic axes and a separation distance between adjacent slots in each of the respective pluralities of slots being equal to λ g1; a broadwall of each branch waveguide (113; 413; 513) includes a distal surface and a respective portion of the array of slots (115; 515) is disposed on the distal surface, the BFN includes a second feed waveguide and a second set of branch waveguides (217; 417; 517), each branch waveguide in the second set being configured to operate in a frequency band having a second characteristic waveguide wavelength λ g2; a proximal portion of the second set of branch waveguides is communicatively coupled with the second feed waveguide; the first set of branch waveguides (113; 413; 513) is not communicatively coupled with the second feed waveguide; the second set of branch waveguides is not communicatively coupled with the first feed waveguide; the array of slots (115; 515; 219; 519) includes a plurality of slot pairs, each slot pair including a respective first slot (115; 515) associated with the first set of branch waveguides and a respective second slot (219; 519) associated with the second set of branch waveguides; each radiating element (318; 418) is communicatively coupled with a respective one of the plurality of slot pairs; and wherein respective pairs of branch waveguides of the first set of branch waveguides (113; 413; 513) and the second set of branch waveguides (217; 417; 517) are interlaced. the BFN includes a first feed waveguide and a first set of branch waveguides (113; 513), each branch waveguide in the first set being configured to operate in a frequency band having a first characteristic waveguide wavelength λ g1; a proximal portion of the first set of branch waveguides is communicatively coupled with the first feed waveguide; a distal portion of the first set of branch waveguides comprises an array of slots and is communicatively coupled by way of the array of slots with a plurality of radiating elements (318; 418); the array of slots is configured as a honeycomb-like triaxial lattice having three characteristic axes (133, 134, 135), respective pluralities of slots being aligned with each of the three characteristic axes and a separation distance between adjacent slots in each of the respective pluralities of slots being equal to λ g1; a broadwall of each branch waveguide (113; 413; 513) includes a distal surface and a respective portion of the array of slots (115; 515) is disposed on the distal surface, the BFN includes a second feed waveguide and a second set of branch waveguides (217; 417; 517), each branch waveguide in the second set being configured to operate in a frequency band having a second characteristic waveguide wavelength λ g2; a proximal portion of the second set of branch waveguides is communicatively coupled with the second feed waveguide; the first set of branch waveguides (113; 413; 513) is not communicatively coupled with the second feed waveguide; the second set of branch waveguides is not communicatively coupled with the first feed waveguide; the array of slots (115; 515; 219; 519) includes a plurality of slot pairs, each slot pair including a respective first slot (115; 515) associated with the first set of branch waveguides and a respective second slot (219; 519) associated with the second set of branch waveguides; each radiating element (318; 418) is communicatively coupled with a respective one of the plurality of slot pairs; and wherein respective pairs of branch waveguides of the first set of branch waveguides (113; 413; 513) and the second set of branch waveguides (217; 417; 517) are interlaced.