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A reference measurement setup for the deployment and test of multiple-input-multiple-output (MIMO) arrays is essential when a new array is optimized according to specific application requirements. For such a reason, in this article, a testbed for the performance assessment of 1-D and 2-D MIMO arrays at 300 GHz for radar applications is proposed. The system is based on monolithic microwave integrated circuit (MMIC) to dielectric waveguide (DWG) transitions, which makes the array element positions independent of the positions of the MMICs on the hardware back-end. The antenna arrays to be tested are fed through DWGs, which are extremely mechanically flexible and easy to reconnect to different antenna arrays. The effectiveness of the proposed testbed is demonstrated by the test of three different antenna arrays made of three transmitters and two receivers. One 1-D MIMO array and two 2-D MIMO arrays are designed for this purpose. The antenna positions are optimized through a genetic algorithm based on the analysis of the ambiguity function associated with the array. This optimization shows that even with a reduced number of array elements, it is possible to perform direction of arrival (DoA) estimation on both azimuth and elevation angles at 300 GHz. The optimized antenna arrays are then tested through the proposed system. An analysis of the measured ambiguity functions associated with the arrays shows a strong agreement with the simulated ones and demonstrates the functionality of the system.

This article reports a 223–276-GHz monostatic frequency-modulated continuous-wave (FMCW) radar transceiver (TRX) chip. The TRX is suitable for building massive multiple-input multiple-output (MIMO) radar arrays in the daisy-chain topology because of its cascadable feature based on the injection-locking feedthrough technique. The TRX is based on $18\times $ frequency multiplication chain that can be fed by either an external signal generator (SG) or its internal voltage-controlled oscillator (VCO). The modulation bandwidth (BW) is about 53 GHz when the internal VCO is activated, resulting in a range resolution of better than 3 mm. The peak output power is 3.1 dBm at 240 GHz with a 3-dB BW of 41 GHz. Its receiver (RX) channel is based on the in-phase/quadrature architecture enabling complex signal sampling. The minimum single-sideband (SSB) noise figure (NF) is 18.7 dB at 255 GHz, and the average value is 20.7 dB. The TRX chip includes an on-chip antenna coupled with a silicon lens, offering a peak effective isotropic radiated power (EIRP) of 27 dBm at 240 GHz. The TRX consumes a dc current of 234 and 270.1 mA from a single supply voltage of 3.3 V for external and internal VCO operations, respectively. The chip occupies a total area of 2.7 mm 2 ( $2.16\times1.26$ mm).