Electron Spin Resonance (ESR) spectroscopy is a powerful analytical technique broadly used to study materials characterized by unpaired electrons. This technique is applied in chemistry, physics, biology, and material science. Since 2008, Prof. Boero group has worked on a new methodology for the detection of ESR signals. This new approach is based on single chip integrated electronic oscillators. The ESR signal is detected by resolving the sample-induced frequency shift of the electronic oscillator caused by change in the sample magnetization induced by the externally applied magnetic field. The flexibility provided by the use of integrated electronics has, as counterpart, a limit in the maximum achievable Q-factor of the microcoils. This limit turns into bounding the achievable noise performance of the oscillators, and consequently, the attainable spin sensitivity and concentration sensitivity. In this work, providing a path to overcome these limitations, we present, for the first time, the design, characterization and exploitation for ESR spectroscopy experiments of microwave superconducting oscillators based on superconducting planar resonators. Superconducting planar resonators are high Q-factor devices, harnessing the unique properties of superconducting materials. To realize the oscillators, superconducting resonators with high Q-factors are connected in a positive feedback loop. This approach is accomplished using different feedback electronics configurations and different low noise transistors in combination with the resonators fabricated in NbTi and YBCO. As a first step, NbTi is used for the first time for the realization of superconducting resonators. The realized planar superconducting resonators demonstrate comparable performance with respect to other materials previously studied in literature, achieving Q-factors higher than 10000 at 6.8 GHz and 3 K, as well as Q-factors greater than 1000 in the sub-GHz frequency range at 3 K and up to 2 T. Superconducting resonators are also realized using YBCO. Performance comparable to literature are obtained also for the fabricated YBCO resonators, with recorded Q-factors of the order of 11000 at 3 K, with small performance perturbation up to 5 T. Three different oscillators are assembled and used to perform ESR experiments. At first, a 600 MHz oscillator is realized. It is based on a YBCO resonator and on an HBT SiGe transistor. Afterwards, two 1.7 GHz oscillators are assembled. They are based respectively on a YBCO and a NbTi resonator connected to a pHEMT Colpitts based feedback electronics. All the oscillators are characterized in cryogenic environments, both in dewars of liquid N2 (77 K) or liquid He (4.2 K) and in a superconducting magnet. The realized oscillators achieve a frequency noise of about 20 mHz/Hz^(1/2) at 630 MHz and 100 kHz from carrier and a frequency noise of about 9 mHz/Hz^(1/2) at 1.7 GHz and 100 kHz from carrier. The ESR experiments performed with small crystal of BDPA between 4 K and 77 K, demonstrated absence of signal broadening and proved adherence with Curie law for temperatures = than 10 K. The best spin sensitivity, attained with the YBCO based 600 MHz oscillator, is of about 1x10^10 spins/Hz^(1/2) with a sample volume of 3 nL on a sensitive volume of 0.7 uL. The best concentration sensitivity, achieved with the NbTi based 1.7 GHz oscillator, is of about 3x10^18 spins/Hz^(1/2)m^3 with a sample volume of 11 nL on a sensitive volume of 19 uL.