A resonance type impedance sensor (81-83; 93-96) which is a multicoil open-core or air-core inductor configured to emit probing electromagnetic field and perceive response from an object under test created by its electromagnetic impedance, said sensor comprising at least two coils (12, 13; 61, 62; 71, 72; 101, 102; 111, 112; 122, 123), at least one coil of the at least two coils being at least one excitation coil (12; 61; 71; 101; 111; 122) and at least one other coil of the at least two coils being at least one sensing coil, the excitation coil being connectable to at least one alternating current source with frequency sweep (11; 121) and configured to provide said at least one sensing coil (13; 62; 72; 102; 112; 123) with electromagnetic energy in order to maintain electromagnetic resonance oscillation of said sensing coil (13; 62; 72; 102; 112; 123), the sensing coil (13; 62; 72; 102; 112; 123) being connectable to at least one data processing system (14; 124) and configured to emit said probing electromagnetic field and perceive response from an object under test, wherein: (i) upon electrical connection to said current source (11; 121), said at least one excitation coil (12; 61; 71; 101; 111; 122) is capable of propagating an energy to said at least one sensing coil (13; 62; 72; 102; 112; 123), which is arranged to generate a probing electromagnetic field, (ii) said at least one sensing coil (13; 62; 72; 102; 112; 123) is designed in such a way that its intrinsic inductance L, capacitance C, and resistance R parameters provide said at least one sensing coil (13; 62; 72; 102; 112; 123) with capability of exhibiting its resonant behavior at appropriate predetermined frequency for measuring of object under test (64; 104; 115) impedance, said object under test (64; 104; 115) capable of being at least one of conductive, semi-conductive and non-conductive, and (iii) said at least one sensing coil (13; 62; 72; 102; 112; 123) is arranged to use only its intrinsic capacitance in order to exhibit resonant behavior at appropriate predetermined frequency for measuring impedance of at least a part of said object under test (64; 104; 115) falling within a sensing area or range of said at least one sensing coil (13; 62; 72; 102; 112; 123). (i) upon electrical connection to said current source (11; 121), said at least one excitation coil (12; 61; 71; 101; 111; 122) is capable of propagating an energy to said at least one sensing coil (13; 62; 72; 102; 112; 123), which is arranged to generate a probing electromagnetic field, (ii) said at least one sensing coil (13; 62; 72; 102; 112; 123) is designed in such a way that its intrinsic inductance L, capacitance C, and resistance R parameters provide said at least one sensing coil (13; 62; 72; 102; 112; 123) with capability of exhibiting its resonant behavior at appropriate predetermined frequency for measuring of object under test (64; 104; 115) impedance, said object under test (64; 104; 115) capable of being at least one of conductive, semi-conductive and non-conductive, and (iii) said at least one sensing coil (13; 62; 72; 102; 112; 123) is arranged to use only its intrinsic capacitance in order to exhibit resonant behavior at appropriate predetermined frequency for measuring impedance of at least a part of said object under test (64; 104; 115) falling within a sensing area or range of said at least one sensing coil (13; 62; 72; 102; 112; 123).