Synthetic Quasi-TEM Meandered Transmission Lines for Compacted Microwave Integrated Circuits

Abstract

This paper presents a two-dimensional transmission line (2-D TL) that supports quasi-TEM propagation mode and reduces problems associated with compacted meandering of microstrip (MS) on propagation constants and the characteristic impedances commonly observed in conventional one-dimensional MSs. The proposed 2-D TL comprises two layers of metallic surfaces on either side of a dielectric substrate. The top metal surface is a meandered connection of a unit cell with a central patch and connecting arms. The bottom surface is a meshed 2-D periodical ground plane, whose etched portion complements the patch portion of the top surface, forming a complementary-conducting-strip (CCS) TL, enabling a combination of an MS and MS with the tuning septa in a unit cell. Both theoretical and experimental investigations of the CCS TL agree well and demonstrate that it is much less susceptible to the effects of meanderings on the propagation constant and characteristic impedance than an MS for the same meandered pattern. Two design examples are presented to demonstrate the potential for a CCS TL for miniaturizing microwave passive circuits with minimal losses. The first example involves a 5.4-GHz CCS four-port rat-race hybrid realized in RO4003 and reduces the area of original MS design by 87%. The second example illustrates the applicability of a CCS TL to a monolithic RF integrated circuit using a first-pass design of a 5.2-GHz CMOS oscillator incorporating a CCS TL as a resonator with an area totaling 500 600 m 2 including pads base on Taiwan Semiconductor Manufacturing Company's 0.25-m 1P5M CMOS process techniques.

K-band 100.8 mW beamforming SOC with 249.8 ± 22.8 pico-second group-delay in 0.13 µm CMOS

“…2 shows the first kind of the on-chip transmission line, so-called the multiple complementary-conducting-strip transmission line (MCCS-TL). The conventional single CCS-TL had been extensively demonstrated with its great advantages on the guiding characteristics syntheses [12], more than 50% transmission-line component miniaturization [9], and the superior isolation to integrate the components in RF SOCs [13]. The concept of the MCCS-TL was firstly reported in [14] to realize the 1.57 GHz half-wavelength resonator and K-band power divider in 0.18 µm CMOS 1P6M process [15].…”

“…Section 2 reports the architecture of the proposed beamforming SOC in details to illustrate how to reduce the group delay variation in the receiving path of the proposed architecture. All the TL elements in the passive attenuators and phase shifter [8] are realized by the on-chip synthetic transmission lines [9,10]. The cascode amplifier with dual-feedback loops, as the first stage in each receiving path, provides 20 dB amplifier gain to compensate all the insertion losses of the passive attenuator, phase shifter, and the power combiner.…”

A Compact Wideband Fractal-Based Planar Antenna With Meandered Transmission Line for L-Band Applications

“…The transmission line which feeds the triangular fractal patch has a length l tl of 18.75 mm. The meandered-line slot is also loaded to the transmission line in order to reduce the patch dimension [20,21]. The meander-line has 6 fingers with finger space c p of 1 mm and finger length l p of 2.1375 mm.…”

“…The proposed antenna is designed by exploiting the advantages of fractal geometry and meandered transmission line to develop wideband antenna with light-weight antenna dimension. By using meandered transmission line, the antenna design has not only a low-profile property, but also simple implementation on MMIC [20,21]. The designed antenna will be implemented on a substrate with relative permittivity of 4.3.…”

A miniaturized 10/24-GHz rat-race coupler using synthetic transmission lines on glass substrate

“…In this paper, a miniaturized 10/24-GHz rat-race coupler using synthetic TLs on the glass substrate is presented. The periodical guiding structures offer another degree of freedom for controlling the propagation characteristics of conventional microstrip lines [6]. Moreover, the area-consuming TL layouts are implemented by meandered synthetic TLs with high slow-wave factors and low losses.…”