A magnetic resonance coil, comprising: a radio frequency antenna configured to receive an RF signal emitted from an object, wherein the RF antenna is a non-resonant antenna; and a signal processor coupled to the RF antenna and configured to process the RF signal to generate a processed signal, the signal processor comprising an amplifying circuit, wherein the amplifying circuit comprises: an amplifier configured to amplify the RF signal, wherein an input impedance of the amplifier is greater than 500 Ohms, the amplifier including a first port, a second port, a third port, and a fourth port, wherein the first port is an input port, the second port and the fourth port are bypass ports configured to distribute power or bias a circuit, and the third port is an output port; the amplifying circuit including a first adjusting circuit, a second adjusting circuit, a bias circuit, and a third adjusting circuit, wherein: the bias circuit is electrically connected to a bypass port of the amplifier and configured to distribute power, each of the first adjusting circuit and the second adjusting circuit is coupled to the input port of the amplifier and includes at least one first adjustable component, each of the first adjusting circuit and the second adjusting circuit being configured to adjust an input impedance of the amplifier from a first complex value to a first real value via the at least one first adjustable component, and the third adjusting circuit is coupled to the fourth port and the output port of the amplifier and includes at least one second adjustable component, the third adjusting circuit being configured to adjust an output impedance of the amplifier from a second complex value to a second real value via the at least one second adjustable component. a radio frequency antenna configured to receive an RF signal emitted from an object, wherein the RF antenna is a non-resonant antenna; and a signal processor coupled to the RF antenna and configured to process the RF signal to generate a processed signal, the signal processor comprising an amplifying circuit, wherein the amplifying circuit comprises: an amplifier configured to amplify the RF signal, wherein an input impedance of the amplifier is greater than 500 Ohms, the amplifier including a first port, a second port, a third port, and a fourth port, wherein the first port is an input port, the second port and the fourth port are bypass ports configured to distribute power or bias a circuit, and the third port is an output port; the amplifying circuit including a first adjusting circuit, a second adjusting circuit, a bias circuit, and a third adjusting circuit, wherein: the bias circuit is electrically connected to a bypass port of the amplifier and configured to distribute power, each of the first adjusting circuit and the second adjusting circuit is coupled to the input port of the amplifier and includes at least one first adjustable component, each of the first adjusting circuit and the second adjusting circuit being configured to adjust an input impedance of the amplifier from a first complex value to a first real value via the at least one first adjustable component, and the third adjusting circuit is coupled to the fourth port and the output port of the amplifier and includes at least one second adjustable component, the third adjusting circuit being configured to adjust an output impedance of the amplifier from a second complex value to a second real value via the at least one second adjustable component. the amplifier including a first port, a second port, a third port, and a fourth port, wherein the first port is an input port, the second port and the fourth port are bypass ports configured to distribute power or bias a circuit, and the third port is an output port; the amplifying circuit including a first adjusting circuit, a second adjusting circuit, a bias circuit, and a third adjusting circuit, wherein: the bias circuit is electrically connected to a bypass port of the amplifier and configured to distribute power, each of the first adjusting circuit and the second adjusting circuit is coupled to the input port of the amplifier and includes at least one first adjustable component, each of the first adjusting circuit and the second adjusting circuit being configured to adjust an input impedance of the amplifier from a first complex value to a first real value via the at least one first adjustable component, and the third adjusting circuit is coupled to the fourth port and the output port of the amplifier and includes at least one second adjustable component, the third adjusting circuit being configured to adjust an output impedance of the amplifier from a second complex value to a second real value via the at least one second adjustable component. the bias circuit is electrically connected to a bypass port of the amplifier and configured to distribute power, each of the first adjusting circuit and the second adjusting circuit is coupled to the input port of the amplifier and includes at least one first adjustable component, each of the first adjusting circuit and the second adjusting circuit being configured to adjust an input impedance of the amplifier from a first complex value to a first real value via the at least one first adjustable component, and the third adjusting circuit is coupled to the fourth port and the output port of the amplifier and includes at least one second adjustable component, the third adjusting circuit being configured to adjust an output impedance of the amplifier from a second complex value to a second real value via the at least one second adjustable component.