My customer wants to use HMC1010 in 260~264MHz.

Data sheet of HMC1010 provides reference value for 900MHz and 2100MHz as below.

But, I could not find reference values for low frequency.

Could you pls provide reference values in 260~264MHz?

Tuned SE-interface for signal frequency = 900 MHz

Use R4 = 27Ω, R11 = 82Ω, C3 = 100 pF, L1=6.8nH, C4=5.6pF, R10 = 0Ω.

Tuned SE-interface for signal frequency = 2100 MHz

Use R4 = 27Ω, R11 = 82Ω, C3 = 100 pF, L1=2.4nH, C4=2pF, R10 = 0Ω.

If you calculate out the impedances at 900 MHz, you get

ZC3 = 1.7 ohms

ZC4 = 31.5 ohms

ZL1 = 38 ohms

So if you combine all of these in a rough scalar fashion you get

Zin = 27 || (31.5 + (38||150) (150 ohms is the differential input impedance of the HMC1010)

= 62 ohm

If you do a similar calculation at 2100 MHz you get a similar input impedance. Because we are doing this rough scalar combination, the answer is a bit off. If you did a correct vector combination, my sense is that you would get an answer that is closer to 50 ohms.

So for 262 MHz, you need to scale up L1 and C4 to something around 20 nF and 20 pF respectively. I'd also increase C3. In the 900 and 2100 MHz examples, the impedance of C3 is low. So it's essentially an ac short that is not contributing to the match. However at 262 MHz, the 100 pF impedance of C3 becomes 6 ohms. So I would suggest increasing C3 to around 400 pF to reduce its impedance to 1.25 ohms.

I think that some trial and error is required. So I'd suggest trying the above values, then check the S11 and do an input power sweep. In terms of trial and error, I would leave C3 fixed and experiment with different values for L1 and C4.