Investigation On Interdigital Left-Handed Microstrip Antenna

Possessing many attractive advantages, such as low profile, light weight, easily conformal to carriers and etc, microstrip antennas (MSAs) have been widely applied in many areas. However, traditional MSAs are still rather large for modern communication at low frequency (VHF/UHF). Thus, the technology of miniaturization of MSAs has become one of the research focuses. Unfortunately, present miniaturized MSAs, suffering from low gains, are limit their applications. Therefore, it is important to develop a MSA with higher gain and smaller volume.Compared with traditional transmission lines, composite right/left-handed transmission lines (CRLH TLs) possess lager and controllable phase propagation constant, so they can realize certain electric length within smaller physical dimension. Theoretically, it is expected that left-handed microstrip antennas composed of CRLH TLs can realize higher gain with smaller area.First, by analyzing the effects of parameters of interdigital left-handed microstrip antenna (ILH-MSA) structure on radiation performances, the available ranges of parameters to ensure the performance of ILH-MSA have been obtained. Then, an L-band ILH-MSA has been designed and fabricated as an example. Compared with a traditional MSA, the size of the present ILH-MSA has been reduced largely with comparable gain. Besides, a 4×4 ILH-MSA array has been designed, fabricated and measured. Good agreement between measured and simulated results verified present design. Finally, the array composed of present ILH-MSA has been studied theoretically.