Design of millimetre-wave antennas on low temperature co-fired ceramic substrates: Master's thesis

In this work, implementation possibilities of millimetre-wave antennas fabricated with low temperature co-fired ceramic (LTCC) technology are investigated. Especially, microstrip antennas operating at 60 GHz frequency band are designed, modeled, manufactured and tested. LTCC is a modern packaging technology which enables manufacturing of multilayer components and modules with high performance up to millimetre-wave region. Benefits of the LTCC technology are high packaging density, low dielectric and conductor losses, reliability and stability. The challenges of the LTCC technology are related to the manufacturing tolerances which become critical for operation of the antennas at 60 GHz frequency band. In the literature review, the basics of antenna theory are presented and common antenna parameters are introduced. Issues related to antenna arrays are also introduced. Then, basic characteristics of microstrip antennas are presented, followed by the introduction of the LTCC technology. Several types of microstrip antennas are designed and modeled with numerical simulation software. Two types of antennas are also modeled with simulation code implemented by the author. The functionality of fabricated antennas is validated by conducting scattering parameter and radiation pattern measurements. Measurement results agree quite well with the simulated ones. Small deviations between simulated and measured results are caused by the differences in designed and realised dimensions of the antennas. Return loss of -10 dB or better is easily achieved. Impedance bandwidth of the antennas is in the order of 3...6%. Maximum absolute gains vary between 3...4 dB. It is clearly seen from the results that functional antennas can be fabricated with standard LTCC process and materials even for the 60 GHz frequency band.