A high precision embedded combline filter implementation in silicon IPD wafers for X band

This paper demonstrates compact quarter wavelength interdigital filters with embedded metal-insulator-metal (MIM) capacitors using silicon Integrated Passive Device (IPD) technology. The incorporation of integrated capacitors directly in the reference plane permits practical size, loss, and repeatability for transmission line style band pass filters implemented in a wafer technology at X band frequencies. The design and on-wafer measurement of a 0.5mm
²
9GHz combline BPF with 3.6dB insertion loss, 50dB 2
^nd
harmonic rejection and sustained 30dB rejection through 4f0 (>40GHz) is discussed in this paper. Measurements of frequency scalability through design of the MIM capacitors are presented, and resonator coupling coefficients achievable in silicon IPD technology using a combline topology are additionally examined.