Graphene field-effect transistors (FETs) are demonstrated as efficient room-temperature terahertz (THz) detectors. These devices utilize the non-linear response of graphene FETs to oscillating radiation fields at the gate electrode, with contributions from thermoelectric and photoconductive effects. The detectors operate at 0.3 THz with noise equivalent power (NEP) levels below 30 nW/Hz¹/², showing their potential for practical applications. The detectors are based on antenna-coupled graphene FETs, which enable selective responsivity to both the spatial mode and polarization of incoming THz radiation. The devices use a log-periodic circular-toothed antenna for efficient coupling of THz radiation into the FET channel. The performance of the detectors is evaluated by measuring the photovoltage response to THz radiation, which is influenced by the gate voltage and the properties of the graphene material. The results show that the detectors have a responsivity of ~100 mV/W and NEP values as low as ~30 nW/Hz¹/² for bilayer graphene. The detectors are capable of imaging macroscopic samples with high spatial resolution and are suitable for a wide range of applications, including medical diagnostics, process control, and homeland security. The study highlights the potential of graphene FETs as a promising platform for THz detection, with the ability to operate at room temperature and offer high sensitivity and fast response times. The results also suggest that further improvements in performance can be achieved by optimizing the device structure and enhancing the coupling efficiency with the antenna.Graphene field-effect transistors (FETs) are demonstrated as efficient room-temperature terahertz (THz) detectors. These devices utilize the non-linear response of graphene FETs to oscillating radiation fields at the gate electrode, with contributions from thermoelectric and photoconductive effects. The detectors operate at 0.3 THz with noise equivalent power (NEP) levels below 30 nW/Hz¹/², showing their potential for practical applications. The detectors are based on antenna-coupled graphene FETs, which enable selective responsivity to both the spatial mode and polarization of incoming THz radiation. The devices use a log-periodic circular-toothed antenna for efficient coupling of THz radiation into the FET channel. The performance of the detectors is evaluated by measuring the photovoltage response to THz radiation, which is influenced by the gate voltage and the properties of the graphene material. The results show that the detectors have a responsivity of ~100 mV/W and NEP values as low as ~30 nW/Hz¹/² for bilayer graphene. The detectors are capable of imaging macroscopic samples with high spatial resolution and are suitable for a wide range of applications, including medical diagnostics, process control, and homeland security. The study highlights the potential of graphene FETs as a promising platform for THz detection, with the ability to operate at room temperature and offer high sensitivity and fast response times. The results also suggest that further improvements in performance can be achieved by optimizing the device structure and enhancing the coupling efficiency with the antenna.