The influence of a top cover on the leakage from microstrip line

When a microwave integrated circuit is enclosed in a package, the top cover causes the transmission lines used in the circuit to become leaky at a lower frequency than otherwise. This effect is investigated in detail for microstrip line, and is found to be particularly dramatic. The leakage is strong enough to produce spurious effects that can ruin the performance of the circuit. The amplitude behavior is obtained by numerically solving for the current on a covered microstrip line due to a delta-gap source excitation. The results clearly show that a strong leaky mode (LM) is excited and that spurious effects due to the LM and from direct radiation from the source generally become more severe at higher frequencies and when the top cover is brought nearer to the strip.

[1]  D. P. Nyquist,et al.  Identification of propagation regimes on integrated microstrip transmission lines , 1993 .

[2]  David R. Jackson,et al.  Existence of a leaky dominant mode on microstrip line with an isotropic substrate: theory and measurement , 1993, 1993 IEEE MTT-S International Microwave Symposium Digest.

[3]  Mikio Tsuji,et al.  Printed-circuit waveguides with anisotropic substrates: a new leakage effect , 1989, IEEE MTT-S International Microwave Symposium Digest.

[5]  Mikio Tsuji,et al.  Dominant mode power leakage from printed‐circuit waveguides , 1991 .

[6]  David R. Jackson,et al.  Excitation of leaky modes on multilayer stripline structures , 1998 .

[7]  T. Sarkar,et al.  Using the matrix pencil method to estimate the parameters of a sum of complex exponentials , 1995 .

[8]  D. Jackson,et al.  The effect of substrate anisotropy on the dominant-mode leakage from stripline with an air gap , 1995, Proceedings of 1995 IEEE MTT-S International Microwave Symposium.

[9]  R. Marqués,et al.  Integral representation of spatial Green's function and spectral domain analysis of leaky covered strip-like lines , 1995 .

[10]  Krzysztof A. Michalski,et al.  Rigorous analysis of open microstrip lines of arbitrary cross-section in bound and leaky regimes , 1989 .

[11]  Dennis P. Nyquist,et al.  Discrete Higher-Order Leaky-Wave Modes and the Continuous Spectrum of Stripline , 1995 .

[12]  A. A. Oliner,et al.  The Nature of the Leakage from Higher Modes on Microstrip Line , 1986, 1986 IEEE MTT-S International Microwave Symposium Digest.

[13]  David R. Jackson,et al.  Leakage of the dominant mode on stripline with a small air gap , 1995 .

[14]  M. Tsuji,et al.  Simultaneous propagation of bound and leaky dominant modes on printed-circuit lines: a new general effect , 1995, Proceedings of 1995 IEEE MTT-S International Microwave Symposium.

[15]  H. Shigesawa,et al.  Conductor-backed slot line and coplanar waveguide: dangers and full-wave analyses , 1988, 1988., IEEE MTT-S International Microwave Symposium Digest.

[16]  D. M. Pozar,et al.  Full-wave spectral-domain computation of material, radiation, and guided wave losses in infinite multilayered printed transmission lines , 1991 .

[17]  David R. Jackson,et al.  An excitation theory for bound modes, leaky modes, and residual‐wave currents on stripline structures , 2000 .

[18]  David R. Jackson,et al.  Spurious transmission effects due to the excitation of the bound mode and the continuous spectrum on stripline with an air gap , 1999 .

[19]  Mikio Tsuji,et al.  The nature of the spectral gap between bound and leaky solutions when dielectric loss is present in printed-circuit lines , 1993 .

[20]  Leakage fields from planar semi-infinite transmission lines , 1996, IMS 1996.

[21]  David R. Jackson,et al.  Proper and improper dominant mode solutions for a stripline with an air gap , 1993 .

[22]  David R. Jackson,et al.  The theory of surface-wave and space-wave leaky-mode excitation on microstrip lines , 1999 .

[23]  Arthur A. Oliner.  Package Effects Caused by Leaky Modes at Higher Frequencies in Microwave Integrated Circuits , 1999, 1999 29th European Microwave Conference.