Dowon Kim

A Super-Directive Zeroth-Order Resonator Slot Antenna

A zeroth-order resonator (ZOR) working as a slot antenna possessing radiation patterns with higher directivity is presented. A ZOR slot is formed by loading series capacitors and shunt inductors on a thin line placed along the edge of semi-infinite ground plane. The measurements performed at 2.6 GHz show increased directivities of 4.9 and 6.2 dB for slot antennas with 16.8 and 32.8-cm lengths compared to 3 dB for a regular half-wavelength resonant slot.

An X-Band Microstrip Phase Shifter Using an Electromagnetic Bandgap Backplane

A new microstrip compatible phase shifter circuit is introduced. The phase shifter uses a strip-type electromagnetic bandgap (EBG) substrate in place of the solid metal ground plane. Such EBG substrates, when made of ferroelectric materials, can produce variable phase constants useful for phase shifter applications. Test models using two different EBG substrates with dielectric constants of 9.2 and 10.2 showed 44.5 degrees of phase difference with 1.7 dB of added insertion loss at 10 GHz from a line originally 504 degrees long.

A microstrip phase shifter using ferroelectric electromagnetic bandgap ground plane

Phase controlling components are key elements for phased array antennas, which require a large number of expensive phase shifters. A microstrip phase shifter using ferroelectric electromagnetic bandgap (EBG) ground plane is proposed for better system integration.

Millimeter-Wave CMOS On-Chip Dipole Antenna Design Optimization

This paper presents an optimized design of a millimeter-wave on-chip dipole antenna using CMOS process. The serious flaw of the antenna using CMOS process is low radiation efficiency because of high permittivity and conductivity. To overcome the weakness, we need to widen radiation area in air and optimize distance between an antenna and a reflector. The radiation efficiency and bandwidth of the designed antenna are respectively 16.5 % and 22.3 % at 80 GHz. Systematic methods are attempt to analyze an effect on the antenna radiation efficiency. To widen radiation area in air, substrate cut angle and distance between the antenna and chip edge are adjusted. In addition, to optimize distance between an antenna and reflector, substrate thickness and distance between the antenna and a circuit ground plane are adjusted.

A broadband planar patch array resonator antenna

A new microstrip antenna with an improved bandwidth is discussed. The new antenna is built with an array of patches on a thin grounded substrate. The number of patches and the individual patch size can be adjusted for desired antenna performance. A twelve-cell patch array resonator with a unit cell size of 5.5 mm and the total antenna area of 25times16 mm2 was fabricated on a 1.27 mm-thick substrate with dielectric constant of 9.8 for a measurement at 6.8 GHz. The measured planar patch array resonator antenna showed 10-dB return-loss bandwidth of 6.6 percent compared to 1.7 percent of a single square patch antenna.

A Microstrip Phase Shifter Design Using a Switch-Loaded Ground Plate

A microstrip phase shifter design that uses a reconfigurable metal pattern on the EBG ground plate is introduced. The EBG ground plate metal pattern contains a linear array of thin slots with switching devices loaded at the center. This design can vary the phase constant with minimum mismatch loss over a large frequency bandwidth. Several test ground plates without actual switching devices were used to verify the design concept.