Compact 28-GHz subharmonically pumped resistive mixer MMIC using a lumped-element high-pass/band-pass balun

This work reports a novel lump-element balun for use in a miniature monolithic subharmonically pumped resistive mixer (SPRM) microwave monolithic integrated circuit. The proposed balun is simply analogous to the traditional Marchand balun. The coupled transmission lines are replaced by lump elements, significantly reducing the size of the balun. This balun requires no complicated three-dimensional electromagnetic simulations, multilayers or suspended substrate techniques; therefore, the design parameters are easily calculated. A 2.4-GHz balun is demonstrated using printed circuit board technology. The measurements show that the outputs of balun with high-pass and band-pass responses, a 1-dB gain balance, and a 5/spl deg/ phase balance from 1.7 to 2.45 GHz. The balun was then applied in the design of a 28-GHz monolithic SPRM. The measured conversion loss of the mixer was less than 11dB at a radio frequency (RF) bandwidth of 27.5-28.5 GHz at a fixed 1 GHz IF, a local oscillator (LO)-RF isolation of over 35 dB, and a 1-dB compression point higher than 9 dBm. The chip area of the mixer is less than 2.0 mm/sup 2/.     

A new wide-band planar balun on a single-layer PCB

A new wide-band microstrip balun implemented on a single-layer printed circuit board (PCB) is presented in this letter. The proposed planar balun consists of a wide-band Wilkinson power divider and a noncoupled-line broad-band 180/spl deg/ phase shifter. To demonstrate the design methodology, one prototype is realized. The new design was simulated and validated by the measurement. Measured results show that 10-dB return loss of the unbalanced port has been achieved across the bandwidth from 1.7 GHz to 3.3 GHz, or 64%. Within the operation band, the measured return losses for both the two balanced ports are better than -10 dB, and the balanced ports isolation is below -1.5 dB. The measured amplitude and phase imbalance between the two balanced ports are within 0.3 dB and /spl plusmn/5/spl deg/, respectively, over the operating frequency band.     

A Miniaturized Multilayered Marchand Balun Using Coupled Artificial Transmission Lines

A miniaturized Marchand balun is investigated in this letter. The Marchand balun is realized on a six-layered printed circuit board by integration of two coupled artificial transmission line sections. An additional artificial line is inserted in-between the coupled lines for compensating the asymmetry. With the help of the even odd mode analysis, the electrical characteristics of the coupled lines are investigated in detail. The proposed balun has the smallest occupied size among the previous designs on printed circuit boards. It features excellent amplitude and phase imbalance, and a comparable return loss bandwidth as well. The design methodology, simulation, and experimental results are introduced thoroughly in the letter.      

Optimum Design of Wideband Compensated and Uncompensated Marchand Baluns With Step Transformers

This paper presents a design approach for wideband compensated and uncompensated Marchand baluns with stepped-impedance transformers. In order to obtain an equal-ripple bandpass response, conventional Chebyshev polynomials are modified to compensate the effect of the transfer function's dc poles. Unlike the available microwave filter design approaches, which usually require redundant elements, this approach leads to an optimum design by using the minimum number of equal length transmission line elements. Based on this design approach, both compensated and uncompensated Marchand baluns are studied. It is found that increasing difficulty arises when implementing a large bandwidth balun using the widely adopted compensated balun structure. Hence, the uncompensated balun structure becomes a better choice. To validate the proposed design approach, an uncompensated balun is designed on a standard two-sided printed circuit board. The measured results indicate that a return loss greater than 20 dB can be observed from 1 to 7.5 GHz. The phase imbalance is less than 4° and the amplitude is less than 0.5 dB from dc to 7.2 GHz.      

Feed for dual-band printed dipole antenna

A dual-band printed dipole antenna is proposed for WLAN applications in the 2.4 and 5.2 GHz bands. A spur line was etched on the arms of the printed dipole to achieve the dual-band operation. The printed dipole antenna with a simplified matching network is proposed. The novel simplified feed structure consists of a pair of parallel metal strips printed on the opposite sides of the dielectric substrate and connected to a 50 /spl Omega/ microstrip line with a truncated ground plane. This feeding network does not require additional transition devices, such as a T-junction, power divider, tuning stub or microstrip-to-coplanar stripline balun.     

Design of broad-band lumped-element baluns with inherent impedance transformation

This paper reports on a novel lumped balun topology, the second-order lattice balun, with broad-band performance. The design is based on synthetic transmission lines operating as impedance transformers. The characteristic impedance of the synthetic transmission lines may be chosen to obtain inherent impedance transformation. An analytical investigation results in closed formulas for optimum performance over a given bandwidth. It is shown that it is possible to design for equal ripple in amplitude balance and input reflection coefficient. The phase balance is theoretically perfect over the entire bandwidth. The concept is experimentally validated by a 1-GHz prototype fabricated with surface mounted chip components. It exhibits an amplitude balance better than 0.5 dB and a phase balance better than /spl plusmn/8/spl deg/ over an octave bandwidth. The effective area of the prototype is 7 /spl times/ 9 mm/sup 2/.     

Input Impedance Analysis of 1:1 Balun

The 1:1 balun constructed of a bifilar delay line and an inverse 1:1 transformer is analyzed for its input characteristics. As a main result of the analyses, the following results were obtained about the balun in this paper. 1) Resonance occurs when the line length is equal to n (any positive integer) times half of a wavelength of the unbalanced transmission mode. 2) The lower cutoff frequency is determined by electromagnetic coupling coefficient "k/sub m/" when L/sub sigma/ and /spl iota/ are constant. 3) The upper cutoff frequency is also given by a combination of k/sub m/ and k/sub e/, etc. 4) Shortening of the distance between the balun and the ground makes the resonant frequency lower when the balun has a magnetic core or when the electrostatic coupling coefficient "k/sub e/" becomes smaller and k/sub m/ is kept constant. /spl omega//sub OI/ becomes lower. 5) In order to realize a wide-band balun, /spl beta//sub b/ / /spl beta//sub u/ shouId be larger and and /spl beta//sub b/ / /spl omega/ should be kept constant.     

Converting baluns into broad-band impedance-transforming 180/spl deg/ hybrids

A technique for converting baluns into 180/spl deg/ hybrids by adding an in-phase power splitter is presented in this paper. Incorporating the broad-band antiphase and in-phase power splitting characteristics of the balun and power splitter results in a 180/spl deg/ hybrid with broad-band characteristics. This technique also provides a means of achieving perfect matching and output isolation for three-port lossless baluns. Applying this technique to a Marchand balun will result in a broad-band impedance-transforming 180/spl deg/ hybrid. Simple design equations based on the scattering matrix are presented. These theoretical results are validated by an experimental 180/spl deg/ hybrid using a coupled line Marchand balun. It achieves amplitude balance of 0.5 dB and phase balance of less than 5/spl deg/ from 1.2 to 3.2 GHz.     

A complete single-chip GPS receiver with 1.6-V 24-mW radio in 0.18-/spl mu/m CMOS

A compact ultra-broadband MMIC-compatible uniplanar balun has been developed using offset air-gap coupler. The offset air-gap coupler presents tight coupling and low conductor loss, and thus allows the balun to show low loss at mm-wave frequencies. The measured insertion loss was less than 2 dB from 26 to 55 GHz, and amplitude and phase imbalance was less than /spl plusmn/1dB and 5/spl deg/, respectively over a wide frequency range from 27 to 69 GHz.     

低成本宽带90°巴伦的研究与设计

提出并设计了一种低成本宽带90°巴伦电路结构,电路由宽带耦合威尔金森功分器、弱耦合线和扇形阶跃阻抗谐振器级联的宽带90°移相器组成。利用电磁仿真软件HFSS对工作在中心频率为1.65GHz 的微带电路进行建模和仿真。采用PCB工艺制作了电路实物并利用矢量网络分析仪进行测试;对比得出仿真与测试结果十分吻合,该巴伦实测相对带宽大于117.0% (0.65～2.58GHz),带内各端口回波损耗好于12.6 dB,输出端口隔离度大于13.1dB,带内插入损耗小于0.5 dB,相位误差小于90°±7.6°。与现有的结构和设计相比,该巴伦不仅具有更大的工作频带和单层电路布局,而且具有容易加工、成本低的优点。     

Analysis of the equal-delay topology for transformers and hybrid networks

A complete scattering matrix representation for the ideal equal-delay topology for transformers and hybrid networks is presented. It is shown that while the operation of the hybrid as a 180/spl deg/ power combiner, current balun, or voltage balun is essentially frequency independent, the operation as a 0/spl deg/ power combiner or splitter is not. Instead, the isolation between the 0/spl deg/ and 180/spl deg/ ports is finite and frequency dependent. Moreover, the reflection coefficient at the sum port is nonzero and frequency dependent. These characteristics lead to the conclusion that while the equal-delay 180/spl deg/ power splitter/combiner is fundamentally frequency independent, its 0/spl deg/ counterpart is limited to operation well below the fundamental quarter-wave frequency of the constituent transmission lines. Full three-port scattering parameter representations, which are compatible with the calibration and analysis approach given in the CISPR 16-1 specification, are given for the three fundamental transformer and balun types derivable from the equal-delay hybrid: 1 the Guanella voltage balun, 2 the Guanella current balun, and 3 the 180/spl deg/ power divider or terminated hybrid balun, as specified in the CISPR 16-1 specification.     

A wideband vertical transition between co-planar waveguide and parallel-strip transmission line

A wideband vertical transition between co-planar waveguide (CPW) and parallel strip transmission line is presented. It functions as an unbalanced-to-balanced (balun) transformer as well. The transition is realized in back-to-back configurations for 50 /spl Omega/ and 75 /spl Omega/ characteristic impedance cases to verify their transition performances. The CPW-parallel strip-CPW transitions are found to have distinct resonant frequencies where the length of the parallel strips is equal to multiples of half wavelength, which is not characteristic of a single transition, but a result of two CPW-parallel strip transitions interacting with each other. Away from the resonant frequencies, the back-to-back configurations have low insertion loss over wide frequency band.     

Low-Loss and Broadband Asymmetric Broadside-Coupled Balun for Mixer Design in 0.18-$mu{hbox {m}}$ CMOS Technology

This study presents an asymmetric broadside coupled balun with low-loss broadband characteristics for mixer designs. The correlation between balun impedance and a 3D multilayer CMOS structure are discussed and analyzed. Two asymmetric multilayer meander coupled lines are adopted to implement the baluns. Three balanced mixers that comprise three miniature asymmetric broadside coupled Marchand baluns are implemented to demonstrate the applicability to MOS technology. Both a single and dual balun occupy an area of only 0.06 mm². The balun achieves a measured bandwidth of over 120%, an insertion loss of better than 4.1 dB (3 dB for an ideal balun) at the center frequency, an amplitude imbalance of less than 1 dB, and a phase imbalance of less than 5deg from 10 to 60 GHz. The first demonstrated circuit is a Ku-band mixer, which is implemented with a miniaturized balun to reduce the chip area by 80%. This 17-GHz mixer yields a conversion loss of better than 6.8 dB with a chip size of 0.24 mm². The second circuit is a 15-60-GHz broadband single-balanced mixer, which achieves a conversion loss of better than 15 dB and occupies a chip area of 0.24 mm². A three-conductor miniaturized dual balun is then developed for use in the third mixer. This star mixer incorporates two miniature dual baluns to achieve a conversion loss of better than 15 dB from 27 to 54 GHz, and occupies a chip area of 0.34 mm².     

一种无需接地结构的巴伦设计

研究了一种新型的耦合线巴伦结构的设计。该巴伦结构简单,仅包含一对耦合线和一根独立传输线,可在单层PCB板上实现,无需任何接地结构。文中给出了该巴伦的设计公式,并分析了在不同端口阻抗比情况下理想电路的阻抗取值范围。该结构中设计参数灵活,还可以通过改变传输线的阻抗值来调整工作带宽。此外,从设计公式中可看到这种结构也很适合设计具有较大的端口阻抗比的巴伦。文中对设计进行了实物样品加工,其工作频率为1.5GHz。其测试结果与理想电路、三维仿真曲线都很吻合。     

Balancing networks for symmetric antennas .I. Classification and fundamental operation

Emphasis has been placed on the quality of a metrology antenna system that allows it to be represented accurately using analytical or numerical models. Central to this capability is the efficacy of the balancing networks, sometimes referred to as balanced to unbalanced transformers (baluns). In this paper, we classify three fundamental types of baluns and show that all three can be derived from the 180/spl deg/, four-port hybrid network. Balanced antennas driven from coaxial feed lines and operated in the presence of an asymmetric scatterer present an intrinsically unbalanced load to the balun. We show that in such situations the current balun is the only appropriate balun to employ. For numerous antenna metrology applications, in particular, site attenuation measurements, 180/spl deg/, four-port hybrid networks have been employed as baluns. Network relations are derived relating the so-called voltage and current baluns to the 180/spl deg/, four-port hybrid network. It is shown that, in addition to acting as a 0/spl deg/ or 180/spl deg/ power divider, the hybrid network can serve as either a voltage or a current balun depending on the termination at the isolated port. In contrast to the traditional approach, it is shown that when using a 180/spl deg/ hybrid as a balun, the isolated port should be terminated in such a way that the hybrid behaves as a current balun as opposed to a 180/spl deg/ power divider. This will yield experimental results that can be more readily reconciled with models.     

A 90 ns 256K /spl times/ 1 bit DRAM with double-level Al technology

A high-performance 256K /spl times/ 1bit DRAM with double-level Al technology is described. It has a small die size of 8.5 /spl times/ 4.0 mm/SUP 2/, an access time of 90 ns, and a soft error rate of less than 1000 FITs. The first and second Al layers are used as bit lines and word lines, respectively. Double-level Al technology is also applied to periphery circuit regions and contributes to a 15 percent reduction of die size in conjunction with a simplified sense-restore circuit. A compact memory cell (10.9 /spl times/ 6.1/spl mu/m /SUP 2/) with a storage capacitance of over 50 fF is obtained through the use of wafer stepping and dry etch techniques.     

Novel miniaturised wideband baluns for MIC and MMIC applications

Very compact novel planar broadband baluns are described. Each balun consists of two Lange couplers. Less than 0.3 dB and 2.5 degrees for the amplitude and phase balances, respectively, have been measured over the 1.0-2.2 GHz bandwidth for a microstrip balun. As compared with other reported baluns, these baluns are simpler, more compact, easier to design, and fabricated on only one side of the substrate. They are thus very attractive for microwave integrated circuit (MIC) and monolithic microwave integrated circuit (MMIC) applications.<>     

A Broadband Substrate Integrated Waveguide (SIW) Planar Balun

A broadband planar balun is presented in this work that makes use of a substrate integrated waveguide (SIW) technique using a printed circuit board process. The proposed balun structure is able to operate at millimeter wave frequencies and it does not require any tight line coupling sections as frequently used in monolithic microwave integrated circuit balun design. In addition, this balun can be integrated with other planar topologies including nonplanar circuits made of the same substrate for achieving high efficiency. This balun structure consists of a 3 dB SIW power divider and microstrip lines that are placed on both sides of the substrate at balanced ports to obtain an 180deg phase shift. The concept is validated by simulations and measurements. Our measured results suggest that a 10 dB return loss at unbalanced port can easily be achieved across a 42% bandwidth from 19 to 29 GHz. Measured amplitude and phase imbalance between two balanced ports are within 1 dB and plusmn5deg, respectively.     

Coaxially-fed tapered slot antenna

An improved design of the longitudinal tapered slot antenna is presented which incorporates a tapered coaxial line balun. This transformer type offers large bandwidth, allows for the direct connection of coaxial sources and reduces the complexity of the printed circuit. Experimental results for an antenna prototype are presented     

A silicon monolithic spiral transmission line balun withsymmetrical design

In this work, a spiral transmission line balun has been fabricated on a high resistivity silicon substrate. The Marchand-type balun has been designed to have the same physical common ground points for the output transmission lines, which eliminates imbalance due to potential difference at the ground. Return loss is better than 17 dB in the frequency band of 1.6-4.1 GHz, especially 39 dB around 1.9 GHz. The amplitude imbalance is less than 0.3 dB throughout the bandwidth. The phase departure from 180° is less than 20 over the frequency range of 1.6-2.6 GHz. The balun is suitable for MMIC application