# A Low-Band Multi-Gain LNA Design for Diversity Receive Module with 1.2 dB NF
## 4 Experimental Results  
The presented multi-gain, multi-band LNA has been implemented and measured using a 65-nm RSB process. The chip micro-photograph and layout of the whole system as well as LB LNA have been shown in Figure 4a,b, respectively. Figure 4c presents the measurement environment where vector signal generators, shield box, power supply, digital multi-meter, network analyzer, spectrum analyzer, have been applied for measurements. The Printed Circuit Board (PCB) including device under test has been presented in Figure 4d. The die area of the LB LNA including the core LNA, switches, and bumps is 950 \(\upmu\)m \(\times\) 800 \(\upmu\)m. For the measurements, supply voltage is 1 V (LDO output voltage) and the current consumption from G6 to G1 are measured to be 10.8, 6.7, 3.2, 1.3, 1.2, and 1.2 mA, respectively. Figure 5 presents the simulation results of the digitally controllable bias voltage generator for an example voltage in different corner cases and with different \(\mathrm{I_{B}}\) reference currents which can be controlled digitally. As we can see, compared to TT corner, for FF, and SS corners, the values of voltage in an specific reference current, are lower and higher respectively. Furthermore, the value can be controlled by sweeping the \(\mathrm{I_{B}}\) reference current in each corner. As discussed before, this is to control the current of core LNA in different circumstances. Figure 6 shows the simulated G6 to G1 gain-modes for band 8. This figure also incorporates the measured gains for different gain modes in different frequency bands. In the same way, the IIP3 performance of different gain modes and different bands as well as simulated IIP3 for band 8 have been summarized in Figure 7. The best IIP3 has been achieved for G1 mode (the lowest gain) which is almost 12 dBm. Noise figure performance for all gain modes and different frequency bands has been presented in Figure 8. For G6 (the highest gain), the NF remains below 1.9 dB with the best value of 1.2 dB for some cases. Figure 3: A digitally controllable bias voltage generator. Figure 4: (**a**) Chip micro-photograph, (**b**) layout, (**c**) measurement environment, (**d**) PCB and device under test, of the designed low band LNA as a part of diversity RF front-end for 2G/3G/4G/5G multi-mode cellular handsets. Figure 5: Simulation results of the digitally controllable bias voltage generator for an example voltage, in different corner cases and with different \(\rm I_{B}\) reference currents. Figure 6: Simulated and measured gain modes for different bands. Figure 9 illustrates the S-parameter measurement results for different bands in G6 mode. Figure 9 presents the S\({}_{11}\) results for the frequency range of 859-960 MHz and through B26, B8, and LB_AUX1 ports shown in Figure 1. In the same way S\({}_{22}\), S\({}_{12}\), and S\({}_{21}\) measurement results have been presented in Figure 9b,c. The S-parameter measurements for frequency ranges of 728-821 MHz and 617-652 MHz have been conducted through LB_AUX2 and LB_AUX3 ports and the results have been summarized in Figure 9d-f. These results (as well as all the presented results) include the Human Body Model (HBM), Charge Device Model (CDM), Electrostatic Discharge (ESD), protections as well as the 5 PST switch. The phase discontinuity between the different gain-modes has been also verified which remains below \(\pm 10^{\circ}\) for the signals in the same frequency band. An example in 892 MHz is shown in Figure 10.  
Table 1 summarizes the performance and compares it with other works [7; 8; 9; 10; 11; 12]. As we can see, our work has a wide gain range (\(-12\)\(\sim\)18 dB) while covering all the frequency range from 617\(\sim\)960 MHz. Furthermore, both HBM and CDM ESD protections have been applied for this design. This can be considered the reason for the degraded S\({}_{11}\) performance compared to other presented works. This degradation happens for the G5 and G4 gain modes. Otherwise, for other gain modes this value remains below \(-10\) dB.