In this paper, a new balanced-to-balanced power divider/combiner is proposed. By using matrix transformation, two three-port networks for the odd- and even-mode circuit models are deduced, based on the constraint rules of the mixed-mode S -parameters. In order to satisfy the two required scattering matrices simultaneously, the resistances of lumped elements, the characteristic impedances and electrical length of transmission lines are selected appropriately. Then, a planar microstrip structure is designed to realize the proposed balanced-to-balanced power divider/combiner with equal power division. The theoretical, simulated and measured results all show a good mixed-mode performance. In the measurement, the maximum differential-mode transmission coefficient is -3.2 dB, the best differential-mode isolation is 47.2 dB, and the fractional bandwidth of its operating band is approximately 20.8%.

A New Balanced-to-Balanced Power Divider/Combiner

With the development of wireless communication technology, radiofrequency (RF) circuits and integrated circuits are becoming more complex and packing more functionality and signals into an ever closer space, with a high level of electromagnetic interaction between circuit nodes and interference/crosstalk from substrate coupling and free space [1]. Balanced/differential circuit technology has become more important in modern communication systems because of good commonmode rejection that leads to relatively high immunity to environmental noise when compared with the single-ended technology [1]-[3], as shown in Figure 1(a) and (b). For balanced circuits, the differential mode should have excellent out-of-band rejection and high selectivity for the desired frequency band, while the common mode should be suppressed over a wider frequency band. In the past few years, many microstrip balanced filters for single band and dual band with common-mode suppression have been realized [4]-[10], with different balanced networks, balanced driven antennas, balanced amplifiers, and mixers [11]-[18].

The Proper Balance: Overview of Microstrip Wideband Balance Circuits with Wideband Common Mode Suppression

Two new wideband in-phase and out-of-phase balanced power dividing/combining networks are proposed in this paper. Based on matrix transformation, the differential-mode and common-mode equivalent circuits of the two wideband in-phase and out-of-phase networks can be easily deduced. A patterned ground-plane technique is used to realize the strong coupling of the shorted coupled lines for the differential mode. Two planar wideband in-phase and out-of-phase balanced networks with bandwidths of 55.3% and 64.4% for the differential mode with wideband common-mode suppression are designed and fabricated. The theoretical and measured results agree well with each other and show good in-band performances.

Wideband In-Phase and Out-of-Phase Balanced Power Dividing and Combining Networks

A new wideband balanced power dividing/combining network with high isolation is proposed in this paper. The differential/common mode equivalent circuits of the balanced network can be easily reduced based on the matrix transformation. Two double-sided parallel-strip line (DSPSL) 180 $^{\circ}$ phase inverters loaded with four isolation resistors are used to realize high isolation for the power division output ports. A planar wideband balanced network with bandwidth 52.7% of (1.68–2.84 GHz, $\vert S_{{\rm dd}21}, S_{{\rm dd}31}\vert >- 4$ dB) for the differential mode and high isolation for the differential/common mode is designed and fabricated. The measured results show good agreement with the theoretical expectations.

Wideband Balanced Network with High Isolation Using Double-Sided Parallel-Strip Line

A modified Gilbert-cell mixer exhibiting both wideband radio-frequency (RF) and wideband IF performance is presented. With the proposed common-gate RF stage with the cross-coupled complementary transistors, a measured conversion gain of 3-8 dB over an RF band of 1-10 GHz is demonstrated, together with an RF input return loss better than 10 dB. The proposed mixer also incorporates wideband active local oscillator (LO) and IF baluns for matching and testing purposes. An IF bandwidth from 100 MHz to 1 GHz is achieved with a conversion gain variation of less than 2 dB. The measured output return loss within the IF band is better than 10 dB. Fabricated in a standard 0.13- μm CMOS technology, the chip only draws 7 mA from a 1.2-V supply due to the current reuse in the proposed RF stage. The measured input referred 1-dB compression point IP1-dB, third-order input intercept point IIP3, and single-sideband noise figure are better than -16 dBm, - 7 dBm, and 15 dB throughout the entire RF band.

A 1- to 10-GHz RF and Wideband IF Cross-Coupled Gilbert Mixer in 0.13- $\mu\hbox{m}$ CMOS

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.

https://ir.nctu.edu.tw:443/bitstream/11536/5546/1/000276619900016.pdf

Chao-Wei Su

Papers

Wide-IF-Band CMOS Mixer Design