Transmission characteristics of a new type of closed elliptic‐groove waveguide for millimeter waves

Abstract

erly adjusting the parameters of the passive and active components of the schematic can make the LNA work at two different frequency bands at the same time, which is meaningful for the development of multistandard operation devices.The proposed dual-band LNA was fabricated at CSM and was measured using an HP8510C network analyzer with on-wafer RF probes. Figure 10 illustrates the measured S parameters and noise figure. It is shown that the LNA has a power gain of about 25 dB at the first band and a gain of about 10 dB at the second band. Performance details are shown in Table 1. The measured data indicate that the LNA's noise figure is not as good as that of the GaAs devices. This is mainly due to the lossy on-chip integrated inductors in standard CMOS technology. In practice, the parasitic resistance of the low-quality-factor inductors has a severe impact on the LNA's noise performance. Generally, it contributes 30% or even more to the LNA's total noise [8]. Figure 11 shows the die photo of the proposed dual-band LNA. CONCLUSIONA CMOS dual-band low-noise amplifier for Bluetooth and wireless LAN applications has been demonstrated in this paper. The LNA is implemented entirely on a single-chip and can be integrated with other CMOS devices. A method to reduce the gate inductor as well as a procedure for dual-band LNA noise optimization have been presented. The design of the proposed LNA indicates that, due to the ever-continuing downscaling of CMOS technologies, a fully integrated multistandard wireless communication system implemented using a low-cost CMOS process has become possible. INTRODUCTIONThe groove guide, a new kind of transmission line with good performances in millimeter and submillimeter wavebands, has been studied and developed because it has a series of advantages, such as low loss, low dispersion, wide bandwidth, high transmission power for the single-dominant mode, large cross-sectional dimension, and so forth. Rectangular, v-shaped, and circulargroove guides have been comprehensively studied [1][2][3][4]. The circular-groove guide can be easily deformed into an ellipticgroove guide, and the modes will change accordingly. However, the modes in the elliptic-groove guide will not change when the central elliptic groove has some deformation. In addition, the elliptic-groove guide is easy to connect with either the circular or the rectangular guide. It may be divided into open and closed elliptic-groove guides. The closed elliptic-groove guide is superior to the open elliptic-groove guide in many cases. For example, it can prevent electromagnetic energy from leaking out of the guide while it is used to transmit very high power. In particular, the open elliptic-groove guide's advantage of a larger cross-sectional dimension is still retained, and the lengths of parallel plates of the closed elliptic-groove guide are also shortened. Moreover, the difficulty of fixing two parallel plates on the open elliptic-groove guide is thoroughly surmounted, and the closed elliptic-groove guide is influenced less wh...