PASSIVE COMPONENTS, like many other building blocks in the high-
frequency industry, have improved in terms of electrical
performance per unit size over the last five decades. When
looking back over the years at earlier passive components and
assemblies, it is not so much the pure electrical performance
that is striking as much as the advances in packaging that have
taken place over that time. In 1980, for example, one of the
leading suppliers of microwave mixers, Watkins-Johnson of Palo
Alto, CA, made news with their M4 series of flatpack mixers. The
products included the model WJ-M4A with local-oscillator (LO)
and RF range of 10 to 1500 MHz and intermediate-frequency (IF)
range of DC to 1000 MHz. During the same time period, a company
still going strong, Mini-Circuits, was selling coaxial power
dividers for only $39.95 each. The firm's ZAPD line of power
dividers included models from 0.5 to 1.0 GHz, 1.0 to 2.0 GHz,
and 2.0 to 4.2 GHz (Fig. 1). The insertion loss was 0.2 dB for
all models, still considered go