C‐band fully integrated SiGe HBT superharmonic QVCO

Abstract

downward and eventually approaches Ϫ/Ϫ180°. Within the region between 2 /90°and Ϫ 2 /Ϫ90°, plane waves are reflected in-phase, rather than out-of-phase. Next, we removed the FSS-layer to examine its influence on the antenna-system. Although this shifted the resonance frequency, it was still within the desired range (860Ϫ960 MHz), and the input impedance also remained within the acceptable range (Fig. 23); consequently, it should be possible to shrink the size of the antenna by a factor of 1.05. We note from Figure 24 that the directivity shows some minor (around 1.2) differences in the range between 900 and 950 MHz.By comparing the input impedance ( Fig. 25) of the antenna composite, we observe that there is a resonance type of behavior that may be attributed to the FSS-layer, which has its own resonance in this range. The inclusion of the FSS-layer yields a higher level of delivered power (ϳ94%) but the bandwidth is slightly smaller in this case as may be seen from Figure 25. This could be attributed to the relatively narrow frequency range in which we have the AMC behavior.In addition, we found that, in general, while using an AMC shift, the input impedance characteristics shift toward a lower frequency; hence, we can decrease the size of the antenna, though only slightly (5-10%). However, designing the antenna/FSS composite for maximum delivered power is quite difficult because its input impedance as well as the ratio between the real and imaginary parts of this impedance is very sensitive to any change in the antenna length.This leads us to conclude that the gain improvement we realized to the RFID system by using an AMC-structure is at best marginal, and more research is needed to fully analyze the complex behavior of the metamaterials for RFID applications. , The design synthesis of multiband artificial magnetic conductors using high impedance frequency selective surfaces, IEEE Trans Antenna Propagat 53 (2005), pp. 8 -17. ABSTRACT: This paper demonstrates a 4-GHz monolithic SiGe heterojunction bipolar transistor quadrature voltage-controlled oscillator (QVCO) using superharmonic coupling topology. The QVCO at 4.17 GHz has phase noise of Ϫ116 dBc/Hz at 1 MHz offset frequency, output power of Ϫ6 dBm, and the figure of merit Ϫ179 dBc/Hz. The core current consumption is 3.2 mA at 3 V supply voltage. The die size is about 1.4 mm ϫ 1.2 mm.