A 24–44 GHz Broadband Subharmonic Mixer With Novel Isolation-Enhanced Circuit

Abstract

A 24 to 44 GHz upconversion broadband subharmonic mixer with a novel isolation-enhanced architecture is presented through a 0.15 m GaAs pHEMT process. Total chip size including probe pads is less than 1.33 0.82 mm . The isolation-enhanced circuit is constructed from two directional couple lines both formed with three microstrip lines. They are used to enhance the isolation between IF/LO-to-RF and LO-to-IF. IF and RF pre-amplifiers are employed to achieve high conversion gain for subharmonic mixing of anti-parallel diode pairs. Based on the unilateral characteristics of an IF pre-amplifier, the LO/RF-to-IF isolations exhibit substantial improvement. From the measured results, the conversion gain of the mixer is 6.0 to 10.5 dB operating at RF frequency of 24 to 44 GHz. The IF-to-RF, LO-to-IF, LO-to-RF, and 2LO-to-RF isolations are 24.5 to 27.1 dB, 32.4 to 39.6 dB, 20.6 to 24.6 dB, and 48.4 to 65 dB, respectively.

A 24 GHz hydrology radar system capable of wide‐range surface velocity detection for water resource management applications

“…This FOM covers the critical parameters for evaluation of an LNA for low power and NF, high gain, and wide‐bandwidth applications. Table 2 is a summary of the implemented 22.3 ~ 32 GHz CMOS LNA, and recently published remarkable CMOS LNAs with operation frequency around 24 GHz 13‐17 . Clearly, our LNA exhibits comparable gain and IP 1dB , the lowest NF and P DC , and the highest FOM.…”

“…After being divided by the power divider, part of it is doubled in frequency (ie, which becomes 24‐GHz‐band) by the second frequency doubler, and filtered by the band‐pass filter, then sent to the transmitting antenna. The other divided signal (by the power divider) is sent to the LO port of the subharmonic DC mixer to generate equivalently second harmonic (ie, 24‐GHz‐band) LO input signal 12,13 . This causes the corresponding Doppler frequency to be obtained at the IF output of the mixer.…”

“…The RF module of the radar includes a phase‐locked loop (PLL) with micro control unit‐controlled division ratio for generating a stable and tunable (ie, frequency modulation [FM]) 24‐GHz‐band transmitting signal with low phase noise. The radar receives, amplifies, and demodulates the reflected echo signal through a directional narrow‐beam antenna, the proposed low‐noise amplifier (LNA), and the subharmonic down‐conversion (DC) mixer, respectively 12,13 . Then the Doppler frequency‐shift and time difference (between the received and the transmitted signals) are analyzed by the digital signal processing (DSP) module for estimation of the WL and flow velocity.…”

Design of Sub-Harmonic Mixer Mmic for Ehf Satellite Links

“…For this reason, different design techniques have been developed to increase the coupling factor: contributions can be found adopting a spiral shaping [13] or three-conductor approaches [25][26][27]. Reference [28] presents a generalized solution for multi-conductor Marchand-like baluns and illustrates how to reduce a multi-conductor symmetrical coupled line section to a single asymmetrical section.…”

Modified Broadband Ruthroff-Type Transmission Line Transformer Balun for Isolation-Enhanced Passive Mixer Design

“…As one of the essential components of RF communication front-ends, high-performance mixers are widely demanded to economically and efficiently operationalize the up/down spectrum shifting functions of signals. There are various circuit topologies and electrical configurations for mixers, which are commonly categorized into two groups, the active type [ 5 , 6 , 7 , 8 , 9 ] and passive type [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ], further classified as single-ended, single-balanced, double-balanced, triple-balanced, and subharmonic approaches. In addition, the specific selection criteria should be determined based on system specifications, including operating bandwidth, conversion loss, port isolation, and compactness [ 23 ].…”