## 3 Post-Layout Simulation Results
### Low-Pass Filter  
In this section, results of the post-layout simulation of the proposed wideband reconfigurable integrated LPF at different filter order and bandwidth configuration sets are presented. The tuning range of the resistor bank of the 6 th order filter, a cascade of 2 nd and 4 th order filters, for both LP and HP can be seen in Figure 12. As seen from the overlapping bandwidth tuning ranges, resistor bank based frequency tuning is sufficient to compensate bandwidth offset related to technology process corner with a minimum tuning word margin of 5. The filter response for all three configurations of the LPF order at various corner and intermediate bandwidth configurations is show in Figure 13. The gain varies from \(-0.55\) dB to \(-0.84\) dB with a maximum passband ripple of 0.1 dB for the LP across the entire bandwidth tuning range and for all configurations of the filter order. For the same HP configuration, the gain varies from \(-0.26\) dB to \(-0.48\) dB with a maximum passband ripple of 0.75 dB. The small negative gain is caused by resistor bank parameter variations in filter topologies, internal resistance of the transmission gates, and by finite gain of the FDOA. It is possible to compensate this by adding a separate control for either the R\({}_{1}\) and R\({}_{5}\) or the R\({}_{3}\) and R\({}_{4}\) pairs (see Figures 3 and 4). Since margin of the tuning word is at least 5, an offset value for the selected pair can be added when tuning the bandwidth to  
Figure 11: In-band output-referred third-order intercept point (OIP3) and power consumption at different bias control values of the fully differential operational amplifiers used in 2 nd order: (**a**) low frequency path (LP); (**b**) high frequency path (HP). OIP3 input tone configuration: 1 MHz and 1.7 MHz, both tone amplitude \(-10\) dBm. Figure 12: Bandwidth tuning range at different technology process corners for the 6 th order configuration: (**a**) low frequency path (LP), configured for 20 MHz bandwidth; (**b**) high frequency path (HP), configured for 200 MHz bandwidth. compensate the gain variation of the LPF. Lastly it can be noted that the gain control in typical SDR transceivers is implemented by using VGA stages before or after the LPF. 1 dB compression point (P1 dB) for all three configurations of the filter order for LP and HP is shown in Figure 14. The 2 nd order stage has a P1 dB of 14.1 dBm, while the compression point of the 4 th order stage is 9.9 dBm for both LP and HP. Due to cascaded structure of the 6 th order configuration, its P1 dB value is determined by the most nonlinear stage, and therefore it has the same value as the 4 th order stage. Since the capacitor bank are used in the filter for bandwidth selection and minimum bandwidth of the filter is well above the 1/f noise corner, LPF has small NF variation at same load conditions over the entire range of bandwidth control. Due to aforementioned small variations in NF and P1 dB, large signal dynamic range per hertz of the proposed filter is nearly invariant to different sets of bandwidth and order configurations. Total harmonic distortion (THD) for LP and HP is shown in Figure 15. If LP is configured for 20 MHz, THD values for 2 nd, 4 th and 6 th filter order configuration vary from \(-103.1\) dB to \(-91.7\) dB with a 0.2 VPP input and from \(-75.7\) dB to \(-69.9\) dB with a 1 VPP input. One percentage THD is reached with 12 dBm for 2 nd filter order and 8 dBm level input signal for 4 th and 6 th filter order. Figure 13: Low frequency path (LP) and high frequency path (HP) response for all order configurations, tuned to 2.5 MHz, 5 MHz, 10 MHz, 20 MHz, 50 MHz, 100 MHz, and 200 MHz. When HP is configured for 200 MHz, values of the THD for the same configurations of the filter order vary from \(-105.5\) dB to \(-97.4\) dB with a \(0.2\,\mathrm{V}_{\mathrm{PP}}\) input and from \(-79.1\) dB to \(-64.6\) dB with a \(1\,\mathrm{V}_{\mathrm{PP}}\) input.