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In this paper, various architectures of three-dimensional compact microwave balanced to unbalanced (balun) transformers for Bluetooth/WiFi antenna applications are successfully designed and optimized using the design of experiments (DOE) approach. Two different multilayer topologies, one microstrip and one stripline, are investigated on low temperature co-fired ceramic (LTCC) substrate. The design goals for both baluns are perfectly balanced outputs from 2 to 3 GHz and a resonant frequency of exactly 2.4 GHz. It is demonstrated, using only eight simulations, that perfectly balanced outputs are not possible under the given conditions in the case of the microstrip balun. Nevertheless, the stripline balun can be optimized due to its almost symmetrical structure, and both simulations and measurement results verify the conclusions. The DOE method is very simple to implement and gives a clear understanding of the system behavior at the beginning of the design process, reducing the amount of work required for achieving the design goals by orders of magnitude compared to the widely used trial-and-error approach. The matching and unique measurement issues regarding the calibration, placement of probes and the de-embedding of the microstrip to coplanar waveguide transitions are discussed in detail for the optimized stripline balun. This technique can be easily applied to the fast and efficient optimization of complicated radiation structures, such as reconfigurable or multilayer multiband antenna arrays.

In this paper an antenna is presented that satisfies the two-fold radiation pattern requirement of communication systems utilizing both geostationary satellites and terrestrial transponders for coverage of mobile terminal away from the equator. A typical requirement for such a system is a low profile antenna that maximizes left-hand circularly polarized radiation in the satellite viewing angle, from 30/spl deg/ to 70/spl deg/ from zenith, and vertically polarized radiation in the terrestrial station viewing angle, from 70/spl deg/ to 90/spl deg/ from zenith. This dual radiation pattern coverage is achieved by integrating a small four arm spiral with a top loaded monopole into a single compact volume, an antenna termed a spirapole.

Future wireless communications systems require better performance, lower cost, and compact RF front-end footprint. The RF front-end module development and its level of integration are, thus, continuous challenges. In most of the presently used microwave integrated circuit technologies, it is difficult to integrate the passives efficiently with required quality. Another critical obstacle in the design of passive components, which occupy the highest percentage of integrated circuit and circuit board real estate, includes the effort to reduce the module size. These issues can be addressed with multilayer substrate technology. A multilayer organic (MLO)-based process offers the potential as the next generation technology of choice for electronic packaging. It uses a cost effective process, while offering design flexibility and optimized integration due to its multilayer topology. We present the design, model, and measurement data of RF-microwave multilayer transitions and integrated passives implemented in a MLO system on package (SOP) technology. Compact, high Q inductors, and embedded filter designs for wireless module applications are demonstrated for the first time in this technology.