This study investigates the transport properties of two finite and parallel armchair graphene nanoribbons (A-GNRs) connected to two semi-infinite leads of the same material. Using a single π-band tight-binding Hamiltonian and Green's function formalisms within real-space renormalization techniques, the density of states (DOS) and conductance of these systems are calculated, considering the effects of geometric confinement and a uniform magnetic field applied perpendicular to the heterostructure. The results show resonant tunneling behavior and periodic modulations of transport properties as a function of the geometry of the conductors and the magnetic flux through the heterostructure. Aharonov-Bohm-type interference is observed, represented by periodic metal-semiconductor transitions in the DOS and conductance curves. Graphene nanoribbons (GNRs) are quasi-one-dimensional systems based on graphene, with electronic behavior determined by geometric confinement. Controlling these effects through external perturbations or geometric modifications can lead to new technological applications, such as graphene-based composite materials, molecular sensors, and nanotransistors. Resonant tunneling in GNRs can occur in S- and U-shaped ribbons due to quasi-bound states, or in nanoring structures under magnetic fields. Experimental studies have shown that transport response can be modulated by external magnetic fields, with Aharonov-Bohm oscillations observed in certain configurations. The study focuses on the electronic transport modulations due to geometric confinement and magnetic fields. It considers symmetric and asymmetric configurations of the central ribbons, observing interference effects at low energies due to extra spatial confinement, leading to resonant states and tunneling behavior. The interaction of electrons with a uniform magnetic field applied perpendicular to the heterostructure results in periodic transport property modulations, with metal-semiconductor transitions as a function of magnetic flux. The results show that the magnetic field significantly affects the electronic and transport properties of the heterostructures, leading to periodic metal-semiconductor transitions. The electronic levels exhibit rich behavior as a function of the external field, with states pinned at the Fermi level and relativistic Landau level behavior at low energies. The study also highlights the importance of these effects in potential electronic device applications, such as on/off switches, by controlling the magnetic field intensity. The results are valid in low-temperature limits and in the absence of strong disorder.This study investigates the transport properties of two finite and parallel armchair graphene nanoribbons (A-GNRs) connected to two semi-infinite leads of the same material. Using a single π-band tight-binding Hamiltonian and Green's function formalisms within real-space renormalization techniques, the density of states (DOS) and conductance of these systems are calculated, considering the effects of geometric confinement and a uniform magnetic field applied perpendicular to the heterostructure. The results show resonant tunneling behavior and periodic modulations of transport properties as a function of the geometry of the conductors and the magnetic flux through the heterostructure. Aharonov-Bohm-type interference is observed, represented by periodic metal-semiconductor transitions in the DOS and conductance curves. Graphene nanoribbons (GNRs) are quasi-one-dimensional systems based on graphene, with electronic behavior determined by geometric confinement. Controlling these effects through external perturbations or geometric modifications can lead to new technological applications, such as graphene-based composite materials, molecular sensors, and nanotransistors. Resonant tunneling in GNRs can occur in S- and U-shaped ribbons due to quasi-bound states, or in nanoring structures under magnetic fields. Experimental studies have shown that transport response can be modulated by external magnetic fields, with Aharonov-Bohm oscillations observed in certain configurations. The study focuses on the electronic transport modulations due to geometric confinement and magnetic fields. It considers symmetric and asymmetric configurations of the central ribbons, observing interference effects at low energies due to extra spatial confinement, leading to resonant states and tunneling behavior. The interaction of electrons with a uniform magnetic field applied perpendicular to the heterostructure results in periodic transport property modulations, with metal-semiconductor transitions as a function of magnetic flux. The results show that the magnetic field significantly affects the electronic and transport properties of the heterostructures, leading to periodic metal-semiconductor transitions. The electronic levels exhibit rich behavior as a function of the external field, with states pinned at the Fermi level and relativistic Landau level behavior at low energies. The study also highlights the importance of these effects in potential electronic device applications, such as on/off switches, by controlling the magnetic field intensity. The results are valid in low-temperature limits and in the absence of strong disorder.