Analysis and Design of a High-Coupling-Factor Marchand-Balun Variant Suitable for Standard Silicon IC Process and Its Wide-Band Gilbert Mixer Application
In this paper, a planar Marchand balun and its modification version are analyzed and designed on the standard lossy silicon substrate of <inline-formula> <tex-math notation="LaTeX">$10~\Omega $ </tex-math></inline-formula>-cm resistivity. The analysis shows that bot...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
IEEE
2024-01-01
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| Series: | IEEE Access |
| Subjects: | |
| Online Access: | https://ieeexplore.ieee.org/document/10734109/ |
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| Summary: | In this paper, a planar Marchand balun and its modification version are analyzed and designed on the standard lossy silicon substrate of <inline-formula> <tex-math notation="LaTeX">$10~\Omega $ </tex-math></inline-formula>-cm resistivity. The analysis shows that both Marchand balun’s outputs are always equal in magnitude and opposite in phase within all frequency ranges even on a lossy silicon substrate. The high-coupling-factor modified Marchand balun has a much wider operation bandwidth than the prototype. Additionally, the multi-layer-metal stacking capability in silicon IC technology favors implementing the coupled line with a high coupling factor. Two Marchand baluns are formed by two back-to-back <inline-formula> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula>/4 coupled lines. The modified one has the duality topology to the original Marchand balun in structure but with a higher coupling factor when both Marchand baluns are designed with the same characteristic impedance, the geometric mean impedance of the even-/odd-mode characteristic impedances, of the constituent coupled lines. These two types of Marchand baluns are implemented on a standard silicon substrate, and obviously the modified Marchand balun has a better performance with outputs of <inline-formula> <tex-math notation="LaTeX">$180\pm 6^{\circ }$ </tex-math></inline-formula> phase difference and ±0.5 dB magnitude imbalance from 4 GHz to 27 GHz. The maximum transmission coefficient is approximately −6 dB, and the 3-dB fractional bandwidth is 148%. Finally, two wideband Marchand balun applications in a Gilbert micromixer are demonstrated using 0.35-<inline-formula> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>m SiGe BiCMOS technology. The modified Marchand balun integrated at the LO stage of the mixer offers more than 30% operation bandwidth than the conventional Marchand balun does. |
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| ISSN: | 2169-3536 |