Wideband Millimeter-Wave Power Divider and SPDT Switch Using Inverting Spiral-Coupled-Line

Abstract

We demonstrate the design and analysis of wideband Wilkinson power divider and SPDT switch using inverting spiral-coupled-line (CL). The SPDT switch constitutes two equivalent <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> /4 transmission-lines (TLs) and two DTMOS switches. For the power divider and the SPDT switch, the inverting spiral-CL has negative and positive mutual inductance in delta and star configuration, respectively. <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C_{1}$ </tex-math></inline-formula> (in the R1C1 isolation network) of the power divider and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C_{P3,R}$ </tex-math></inline-formula> (in the equivalent <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> /4-TL) of the SPDT switch can be reduced to a negligible level. Due to the symmetrical lumped-distributed structure, the power divider attains great TL-length reduction (from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> /4 to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> /9) and amplitude imbalance (AI) and phase difference (PD) enhancement. And the SPDT switch achieves prominent TL-length reduction (from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> /4 to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> /11), and insertion loss (IL) and linearity improvement. At 33 GHz, the power divider achieves <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S_{32}$ </tex-math></inline-formula> of −43 dB, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S_{21}$ </tex-math></inline-formula> of −4.055 dB, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S_{31}$ </tex-math></inline-formula> of −4.051 dB, AI of −0.004 dB, and PD of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-0.117^{\mathrm{ o}}$ </tex-math></inline-formula> . For 0–50 GHz, S11, S22, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S_{33}$ </tex-math></inline-formula> are better than −10 dB, and the magnitude of AI and PD are smaller than 0.011 dB and 0.246°, respectively. The normalized area of the power divider is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.08\times 10^{\mathrm{ -4}}\lambda _{0}^{2}$ </tex-math></inline-formula> , the smallest value ever reported. The SPDT switch occupies a small area of 0.017 mm2, and achieves IL of 0.8-2 dB, isolation of 27.3-35.8 dB, and input 1 dB compression point (P1dB) greater than 27 dBm for 11–35 GHz, one of the best IL and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$P_{\mathrm{ 1dB}}$ </tex-math></inline-formula> results ever reported.