Avoiding cross talk and feed back effects in packaging coplanar millimeter-wave circuits

Abstract

The impact of the packaging configuration on cross talk and feed back effects caused by parasitic substrate modes is investigated for coplanar millimeter-wave circuits. It is demonstrated theoretically and by means of several circuit examples that both the mounting configuration and the thickness of the semiconductor substrate of coplanar MMICs have to be chosen appropriately, in order to avoid circuit degradation or even failure

Influence of backside metallization on a coplanar X-band LNA

“…Further examinations with a spectrum analyzer result in the fact, that no oscillations could be observed, although the resonance effects in the scattering parameters led to this suspect. It turned out more and more, that the resonant behavior was caused by substrate modes due to the backside metallization of the MMIC as described in [3] for mounting on different surfaces. Therefore, the backside metal of the MMIC was removed using a gold etchant and hydrofluoric acid.…”

Waveguide Integrated High-Gain Amplifier Module for Millimeter-Wave Applications

“…Several materials and structures such as dielectric substrate, IC, cavity for IC mounting, waveguide (WG) are used and are integrated into the compact-volume package. Therefore, they can lead troubles such as unwanted substrate modes [6], cavity resonance [7], feedback, or crosstalk due to discontinuities [8,9]. In the previous publications [6][7][8][9], these phenomena were well analyzed and valid models on mechanism were presented.…”

“…Therefore, they can lead troubles such as unwanted substrate modes [6], cavity resonance [7], feedback, or crosstalk due to discontinuities [8,9]. In the previous publications [6][7][8][9], these phenomena were well analyzed and valid models on mechanism were presented. In order to avoid them, resistivity value of the flip-chip carrier [6], resonance condition of the cavity [7], chip mounting configurations [8], and resistive coating on the lid [10] had been investigated.…”

“…In the previous publications [6][7][8][9], these phenomena were well analyzed and valid models on mechanism were presented. In order to avoid them, resistivity value of the flip-chip carrier [6], resonance condition of the cavity [7], chip mounting configurations [8], and resistive coating on the lid [10] had been investigated. Various modules [1,2,6,11] have been successfully implemented by reflecting these investigations.…”

“…Various modules [1,2,6,11] have been successfully implemented by reflecting these investigations. However, for the case of the highgain amplifier block requiring higher than 30 dB, signals reflected from structural discontinuities can cause stability problem due to the feedback effects [8,9]. The radiated signals can enter into one amplifier in the whole high-gain block by reflecting from around structures and they can be amplified.…”