This study introduces a biodegradable sensor with a composite-SRR design for breast tumor analysis. The multi-resonance behavior of the sensor is achieved by etching the SRR structure in the sensor elements. Resonate frequency is tuned by inductive and capacitive nature of the rectangular and circular shaped sensing elements, which is known as hybrid shaped structure of the sensor. The parametric study has resulted in the development of a low-cost, flexible, and readily biodegradable Cellulose Nanofibril (CNF) substrate measuring 30 mm × 100 mm. The proposed sensor is offered the multi-resonating behavior with sharp resonating frequency, there are total 10 resonating dips (S11 < -10 dB) at the frequency of 3.2 GHz, 6.9 GHz, 7.5 GHz, 8.09 GHz,9.4 GHz 10.18 GHz, 16.3 GHz, 17.5 GHz, 19.4 GHz, and 20.3 GHz are offered by the sensor. Breast models, both normal and malignant, are generated within the biomedical exposure environment of Computer Simulation Technology (CST). Further, these models are tested with proposed sensor for tumor detection. Evaluated s-parameters for normal and malignant model (with 10 mm tumor) are exhibited a (10.22 dB) substantial difference in the reflection results. The proposed sensor flexibility and biodegradability compare with existing literature.