Balun

About: Balun is a research topic. Over the lifetime, 5375 publications have been published within this topic receiving 52256 citations. The topic is also known as: Telephone balance unit.

An Active Marchand Balun and Its Application to a 24-GHz CMOS Mixer

Abstract: A fully integrated 24-GHz Gilbert-cell mixer incorporating two on-chip Marchand baluns to convert single-ended signals into differential signals is presented in this paper. One is a passive balun at local oscillator (LO) port to improve isolation between the LO and radio-frequency (RF) ports, and the other is an active balun at RF port to enhance the conversion gain (CG) of the down-conversion mixer. The active balun utilizes complementary cross-coupled pairs (CCPs) to compensate for its resistive losses. Moreover, the gate-to-source capacitances ( $C_{{\text {gs}}}$ ) of the CCPs are also absorbed into coupled lines and then reduce the chip size. The chip area of the active balun is about one quarter of the passive one. The mixer is designed and implemented in a 0.18- $\mu \text{m}$ CMOS technology, and its chip size is 0.38 mm2 including all testing pads. With a power consumption of 18.9 mW and an LO power of 0 dBm, the mixer exhibits a measured CG of 12.8 dB, an input $P_{{\mathrm {in,1~dB}}}$ of −14.5 dBm, and LO-RF isolations better than 43 dB.

A Broadband Planar Balun Using Aperture-Coupled Microstrip-to-SIW Transition

Abstract: Based on low-temperature cofired ceramic (LTCC) technology, a broadband 60-GHz planar balun using longitudinal aperture-coupled microstrip-to-substrate-integrated-waveguide (SIW) transition is proposed. The proposed balun consists of a 3-dB SIW power divider and three longitudinal aperture-coupled microstrip-to-SIW transitions. To broaden the bandwidth of the microstrip-to-SIW transition, a matching post and a fork-type structure is employed in this work. With the proposed microstrip-to-SIW transition, it is very convenient to achieve a frequency-independent out-of-phase or in-phase property, and it does not require a tight coupling factor like the marchand balun. A prototype balun operating at 60 GHz is designed, fabricated and measured. The results show that the proposed balun provides a simulated and measured 10-dB return loss fractional bandwidth of 42.3% and >31.8% (limited by the measurement equipment), respectively. Across the operating frequencies, the measured amplitude imbalance and phase imbalance are within ±0.4 dB and ±5°, respectively.

Novel transmit/receive balun structure

Abstract: A technique for efficient balun duplexing includes providing a switchless path through a balun. In a receive mode, a transmit path is blocked and signal is directed along a switchless receive path. In a transmit mode, a receive path is blocked and signal is directed along a switchless transmit path.

Wide-IF-Band CMOS Mixer Design

Abstract: A wide-IF-band transistor mixer has been designed using a 0.13-?m RF-CMOS process where its RF frequency is 8.7-17.4 GHz, local oscillator (LO) fixed at 17.4 GHz, and IF up to 8.7 GHz. Proper layout arrangement for the Marchand balun has been discussed and then implemented; the output amplitude and phase imbalance are less than 0.5 dB and 1 ° measured in the RF bandwidth. Related theories for the core mixing circuit are explored extensively and verified through simulation; broad bandwidth of the resistive double-balanced mixer is then confirmed in the IF aspect. The designed mixer has more than 10-dB conversion gain, matched RF, IF, and LO ports, and good port isolation over the intended wide bandwidth. The input-referred P1 dB is -17.5 dBm at 9 GHz and -16 dBm at 13 GHz. The third-order input intercept point is -6 dBm at 9 GHz and -5 dBm at 13 GHz. The noise figure is 7 dB at 9 GHz and 12.6 dB at 13 GHz. The power consumption is 40 mW for this 1.3-mm2 mixer chip.

Group delay equalised monolithic microwave integrated circuit amplifier for ultra-wideband based on right/left-handed transmission line design approach

Abstract: A group delay equalised InGaP/GaAs HBT monolithic microwave integrated circuit (MMIC) amplifier with an active balun for ultra-wideband (UWB) application has been developed. The MMIC consists of a broadband amplifier with an active balun and a group delay equaliser. The group delay equaliser was designed based on a theory using a composite right/left-handed (CRLH) transmission line. Adding a right-handed (RH) transmission line to a CRLH transmission line in parallel, a convex group delay characteristic is realised. Since various UWB components have concave group delay characteristics, the group delay equaliser can compensate a concave group delay characteristic of the amplifier in an operation frequency band. In this paper, dispersion, group delay and impedance characteristics for the proposed CRLH/RH circuit have been theoretically analysed. Moreover, a minimised group delay equaliser circuit on an MMIC has been designed and fabricated based on the proposed CRLH/RH circuit. A fabricated group delay equalised InGaP/GaAs HBT MMIC amplifier with an active balun exhibited an improved group delay characteristic compared with the MMIC amplifier without the group delay equaliser. The standard deviations of group delays for a frequency variation in a gain band were decreased from 12.8 to 5.5 ps at S 21 and decreased from 10.3 to 7.3 ps at S 31 .