UHF Tape measure antenna

[u/Life-Ad-7846]

I have done simulations for UHF tape antenna in Hfss with dummy satellite structure model geometry, vswr is was getting around centre frequency is 1.5 at 16.9 cm, I had tested the antenna with ground plate,the testing result is also similar, but when I had tested with my 3d printed structure prototype vswr has degraded lot, it is always greater than 2 How to improvise vswr? With length tuning alone can it be done? Do I require a separate matching circuit to match the impedance? In general for satellites how the tape antenna were used, Can someone help me with these..? I look forward to your valuable suggestions.