In this paper we present the development of low-noise waveguide mixers with NbN/AlN/NbN tunnel junctions at frequency approaching 1THz. The mixer was designed to be compatible with MgO substrate. Mixers of such a design demonstrated much improved receiver sensitivity. The improvement is a result of reduction of signal dissipation in waveguide and leakage into IF port by adopting a full-height w...

A wireless sensor server is developed based on a reconfigurable active smart-antenna/retrodirective array. The system can serve as both a retrodirective array transponder and a smart-antenna receiver simply by changing the frequency of the local oscillator applied to the mixers, enabling it to best utilize its hardware to suit its communication environment. When operating as a direct-conversion...

Smart use of mixers is a relevant issue in radio engineering and in instrumentation design, and of paramount importance in phase noise metrology. However simple the mixer seems, every time I try to explain to a colleague what it does, something goes wrong. One difficulty is that actual mixers operate in a wide range of power (150 dB or more) and frequency (up to 3 decades). Another difficulty i...

A wide variety of voltage mixers and samplers are implemented with similar circuits employing switches, resistors, and capacitors. Restrictions on duty cycle, bandwidth, or output frequency are commonly used to obtain an analytical expression for the response of these circuits. This paper derives unified expressions without these restrictions. To this end, the circuits are decomposed into a pol...

We have developed a low-noise 850 GHz superconductor–insulator–superconductor quasiparticle mixer with NbTiN thin-film microstrip tuning circuits and hybrid Nb/AlN/NbTiN tunnel junctions. The mixer uses a quasioptical configuration with a planar twin-slot antenna feeding a two-junction tuning circuit. At 798 GHz, we measured an uncorrected double-sideband receiver noise temperature of TRX5260 K...

An efficient distortion analysis methodology is presented for analog and RF circuits that utilizes linear-centric circuit models to generate individual distortion contributions due to each nonlinear component in a circuit. The per-nonlinearity distortion results are obtained via a straightforward postsimulation step that is simpler and more efficient than the Volterra series-based approaches an...

This paper presents an integrated frequency hopped transceiver based on a subset of the cdma2000 network specifications. The circuit consists of a phase locked loop (PLL) that generates the hopping carriers, local oscillators (LOs) that generate GHz range carrier frequencies, and a series of mixers. It accepts input data in frequency shift keyed (FSK) format, and also outputs received data in F...

Image rejection ratio in CMOS double balanced mixers is strongly dependent on the balance between its branches. The influence of the mismatches is analyzed theoretically at the system and circuit level. Guidelines that show the maximum acceptable mismatch to meet a given image rejection ratio specification and experimental results are presented.

The theory of noise and conversion loss in millimeterwave mixers, developed in a companion paper, is applied to an 80-120.-GHz mixer. Good agreement is obtained between theoretical and experimental results, and the source of the recently reported “anomalous noise” is explained. Experimental methods are described for measuring the embedding impedance and diode equivalent circuit, needed for the ...