Categorising Microstrip Distributed Elements Coupling Types

Coupling coefficient is a very important parameter in the design of RF/Microwave filters. Understanding the coupling mechanism between resonators is very important for achieving a good filter layout. This paper describes a way to classify the type of couplings exhibited in microstrip distributed element resonators. This method explains the coupling types from the definition of coupling coefficients. All the possible coupling types, i.e. electric coupling, magnetic coupling and mixed coupling, will be discussed. The difference between Type-I and Type-II mixed couplings will be addressed. A comparison between the numerically computed coupling coefficients and those computed using computer aided design software is also presented

New Model for the Effective Permeability of Ferrite Microstrip

This work is to develop a new model for the effective permeability of ferrite microstrips which is based on Wheeler's (1977) microstrip impedance model. The newly developed model for the effective permeability will have some improvements over the well-known model developed by Pucel and Masse (1972). In this model, the transition error (or the discontinuity) from a narrow to wide ferrite microstrip has been removed. Unlike Pucel and Masse's model, where one equation is derived for the narrow ferrite microstrip and another for the wide ferrite microstrip, this model only uses a single equation to predict the effective permeability of the ferrite microstrip for the entire range of widt

High Temperature Superconducting Ferrite Phase Shifter with New Latching Structure

Superconductor ferrite phase shifters are attractive for phased array radar systems. The huge reduction in size and losses mean that smaller systems are possible. This paper reports a new latching structure for a superconducting ferrite phase shifter which is compact in size and has low losses. The total size of the phase shifter is 6.0 cm x 3.0 cm x 2.5 cm including housing. It should be pointed out that two phase shifters can be accommodated in this size. The minimum insertion loss of the designed phase shifter was measured at 0.8 dB. The phase shifter is fabricated using a Yttrium Barium Copper Oxide (YBCO) microstrip meander-line on a one centimeter square low loss sapphire substrate. We press contacted a magnetized ferrite substrate, with a silver ground plane, onto the fabricated YBCO meander-line to obtain non-reciprocal phase shifting. To magnetize the ferrite substrate without causing magnetic field penetration into the high temperature superconductor (HTS), we propose a new latching structure comprising a single ferrite layer with magnetizing coils. This new structure will confine the magnetic field within the ferrite substrate by providing a closed magnetic path. This is achieved by making a large hole at center of the ferrite substrate

A Novel Tap Input Coupling Structure for a Narrow Bandpass Filter using TM010 Mode of a Microstrip Circular Disk Resonator

This paper discusses a new method to couple into the TM010 mode of a microstrip circular-disk resonator. This method can achieve reasonably strong input coupling, which is useful for narrow-band filters with fractional bandwidths of approximately 0.5% and above. A comparison between this newly proposed input coupling structure and the conventional gap input coupling structure will be addressed. A decision threshold for using either the tap input or the conventional gap-coupled input is also explained. Experimental results of a filter fabricated using this novel input coupling structure is also presente

5-pole High-Temperature Superconductor Bandpass Filter at 12 GHz using High Power TM010 mode of Microstrip Circular Patch

This paper presents a five pole Chebyshev bandpass filter using high temperature superconducting (HTS) thin films which employed the symmetrical TM010 mode of a circular patch resonator. The filter is designed with centre frequency of 12 GHz with fractional bandwidth of 0.45%. The design is fabricated using double sided YBCO thin films on a sapphire wafer of size (0.33×22.5×39.0)mm3. The achieved unloaded Q-factor of the resonators in the fabricated filter is about 6,500 giving the filter an insertion loss of about 0.8 dB at centre frequency of 12.14 GH

High Frequency Resistance and Capacitance Measurement for Archaeological Surveying

There are many different ways to map underground archaeological features. The open-ended coaxial probe, described in this paper, is another new prospective method. The principle of this method is to measure the microwave reflection co-efficient at particular points on the surface to map out subsurface features. Apart from non-destructive and low cost, a major advantage of this method is the ease of implementation and the additional data provided. In this paper, the principle of open-ended coaxial probing is discussed, and some experimental result

Microstrip Dual-Band Bandpass Filter Using U-Shaped Resonators

Coupled resonators are widely used in the design of filters with dual-passband responses. In this paper, we present a dual-band bandpass filter using only couplings between adjacent resonators without cross-couplings. The dual-band bandpass filter with centre frequencies of 1747 MHz and 1879 MHz respectively is designed and fabricated using microstrip U-shaped resonators. Using the coupled resonator pair as a dual-band cluster, a miniaturised structure is achieved as compared to the conventional topology. The measured responses agree closely with the simulations

Fisher profiles and perceptions of sea turtle-fishery interactions: case study of East Coast Peninsular Malaysia

The paper focuses on coastal fisheries, particularly examining sea turtle-fishery interactions and determining the socioeconomic profile and perception of local fishers about sea turtle issues along the East Coast of Peninsular Malaysia.Turtle fisheries, Nature conservation, Coastal fisheries, Man-induced effects, ISEW, Malaysia, Malaya, Pahang, Malaysia, Malaya, Kelantan, Malaysia, Malaya, Terengganu,

The Design of Microstrip Six-Pole Quasi-Elliptic Filter with Linear Phase Response Using Extracted-Pole Technique

The development of microstrip filters has been in great demand due to the rapid growth of wireless communication systems in this decade. Quasi-elliptic response filters are very popular in communication systems because of their high selectivity, which is introduced by a pair of transmission zeros. A number of ways of implementing the quasi-elliptic response filter on microstrip have been studied over the last two decades, i.e., the cascaded quadruplet filter, canonical filter, and extracted-pole filter. However, there is very little information in the literature giving the design details for microstrip extracted-pole filters. In this paper, design equations of the extracted-pole filter for microstrip are reviewed. A new class of microstrip filter is also presented here. This class of filter will have a quasi-elliptic function response and at the same time linear phase in the passband. The linear phase of the filter is introduced by an in-phase cross coupling, while the transmission zero is realized using an extracted-pole technique. Experimental results, together with a theoretical comparison between the group delay of this design, and the conventional quasi-elliptic six-pole filter are also presente

Distributed Transmission Line Phase Shifter with Loaded BST Capacitors using Thick Film Technology

A thick-film phase shifter fabricated from screenprinted ferroelectric capacitors and metallization is described. At 30 GHz a phase shift of 4º/dB at 1kV mm-1 was achieved. The phase shift less dependent on frequency than conventional transmission-line phase design