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.

Resistive HEMT mixers for 60-GHz broad-band telecommunication

Abstract: We report two resistive mixers, i.e., a balanced and a balanced image-rejection (IR) mixer for the 60-GHz frequency range. A compact and wide-band method for the local-oscillator (LO) power division is presented. The 56-GHz LO signal, which propagates in a coplanar-waveguide mode, is divided in between the lines of two spiral baluns. Consequently, a smooth and compact transition from even-to-odd propagation mode and an in-phase power division for two singly balanced unit mixers is achieved. As a result, the developed IR mixer occupies only 1.41mm/sup 2/ of chip area. The balanced design achieved 11.5 dB of conversion loss from 57 to 67 GHz with a fixed IF of 5.3 GHz. The corresponding LO suppression was better than 34 dB with 8 dBm of LO power. The IR mixer achieved better than 19 dB of IR ratio and better than 36 dB of LO suppression for an RF frequency from 57 to 66 GHz. The corresponding conversion loss varies from 13 to 16 dB. The measured 1-dB compression point of the IR mixer was at a -13-dBm output power level and the third-order intercept point was at a 4-dBm level.

A 60-GHz Millimeter-wave CMOS Marchand Balun

Abstract: A novel 60-GHz wideband Marchand balun fabricated with a standard 0.18 mum 6-metal-layer CMOS process for millimeter-wave applications is presented. A technique for achieving good balance with the fourth metal layer microstrip conductor is used in the designed Marchand balun. The fabricated CMOS balun uses multilayer coupling with the top two layers. An output matching network is added to improve the output return loss. The measured amplitude imbalance was about plusmn 1.5 dB from 25 to 65 GHz , over the 89% operating frequency band.

Wideband Differentially Fed Dual-Polarized Planar Antenna and Its Array With High Common-Mode Suppression

Abstract: A differentially fed dual-polarized planar antenna with a wide bandwidth and high common-mode (CM) suppression is presented in this paper. The antenna is composed of four folded dipoles that are connected to each other via the coplanar striplines. Two integrated baluns are utilized to excite the folded dipoles simultaneously to realize ±45° linear polarizations. Owing to the loaded shorting stubs, the impedance matching is improved and the operational bandwidth is broadened. Under differential-mode (DM) excitation, the antenna has a superior unidirectional radiation over a wide bandwidth. Under CM excitation, the antenna achieves a high level of CM suppression performance due to the proposed feeding structure. Measured results exhibit that the antenna gains a wide −15 dB differential impedance bandwidth of 51.1% (1.66–2.80 GHz) and a high port isolation of 38 dB between the differential ports. Moreover, the CM reflection coefficient is larger than −1.32 dB within the DM passband, which indicates that the high CM suppression is attained. To further validate the design concept, a $1\times4$ antenna array is fabricated and measured to demonstrate the superior performances of wide bandwidth, high port isolation, high CM rejection, and good unidirectional radiation.

Radio frequency heat applicator for increased heavy oil recovery

Abstract: A radio frequency applicator and method for heating a geological formation is disclosed. A radio frequency source configured to apply a differential mode signal is connected to a coaxial conductor including an outer conductor pipe and an inner conductor. The inner conductor is coupled to a second conductor pipe through one or more metal jumpers. One or more current chokes, such as a common mode choke or antenna balun, are installed around the outer conductor pipe and the second conductor pipe to concentrate electromagnetic radiation within a hydrocarbon formation. The outer conductor pipe and the second conductor pipe can be traditional well pipes for extracting hydrocarbons, such as a steam pipe and an extraction pipe of a steam assisted gravity drainage (SAGD) system. An apparatus and method for installing a current choke are also disclosed.

Ultra-wideband bandpass filter using broadband planar Marchand balun

Abstract: A novel ultra-wideband (UWB) bandpass filter using a planar Marchand balun is proposed. Owing to the different input/output impedances of the planar Marchand balun, the UWB bandpass filter has an adjustable fractional bandwidth from 74 to 114%, by cascading two planar Marchand baluns based on the transversal filter concepts. Detailed design and synthesis procedures for the UWB bandpass filter are provided.